WEEK | GROWTH STAGE | SOIL (ml/Litre) | HYDRO (ml/Litre) |
---|---|---|---|
1 | Seedling/clone | 0.16 | 0.16 |
2 | Seedling/clone | 0.16 | 0.16 |
3 | Growth | 0.16 | 0.16 |
4 | Growth | 0.16 | 0.16 |
5 | Aggressive Growth | 0.26 | 0.16 |
6 | Aggressive Growth | 0.26 | 0.16 |
The quote above was meant to fire something up inside of you, many reading this article will be pro-organic, so that quote may have riled you up and it may have made those undecided about organics raise their eyebrows in interest, eager to read on and find out where this leads? I’ll set my stall out early and say I’m not for or against organic farming, I am most concerned with the impact we’re having on the planet (pro-organic) but also the potential consequences for farmers and the poorer in society that cannot afford to eat or produce organic food (con organic). That’s a little of the outdoor organics we’ll look into, but we’ll also look at organic vs synthetic in the indoor grow rooms and the benefits/ disadvantages of using either method.
To go into every aspect of the benefits or disadvantages of organic growing would require a whole book, instead, this article will raise a few points to consider the whole issue holistically rather than take a one-sided stance.
Organic outdoors - Growing organically outdoors is undoubtedly beneficial for the environment. We’re not using chemical pesticides and we are using fertilisers derived from animal waste or plant-based sources; an excellent way of recycling with food grade end product. That is essentially the definition of growing organically but there are plenty of other benefits such as:
to the roots.
, salinated and ultimately unfarmable.
the soil and also helps buffer against rapid changes in pH.
5) Growing organically actually feeds the organisms that live in the soil, which then form a symbiotic relationship with the plants increasing nutrient uptake.
However, there are always disadvantages to any particular method of growing and these are some of the organic ones;
1) If the soil has too much organic matter (in excess of 5%), it becomes increasingly complex to manage due to the lower temperatures and high moisture content; this would require special tilling procedures and extra work. Seeding the ground has to be left until later in the season (soil too cold) and growth can also be slower.
2) The source of the organic nutrients is very important, elements can be added that accumulate over time and this would adversely affect the nutritional status of the soil and ultimately the crops being grown. A good example is chicken manure, it is high in potassium and over time will alter the cation ratio of the soil, potentially leading to a magnesium or calcium deficiency.
Nutrition and taste - The favourite go-to argument for organic growers is that it tastes better than conventional crops and it’s more nutritious than conventional crops. However, there has yet to be published any evidence to validate this hypothesis. When we taste organic fruit or veg, we simply believe that it must taste better because that’s what we’ve been led to believe, but on countless blind taste trials, it has not been proven. Similarly, with the nutrition of organic vs traditionally grown crops, they are equal in nutritional density, spare for a few studies that show higher vitamin C levels in leafy green salads. In addition to this, scientific taste tests have shown that when half of the food is labelled organic and the other half labelled regular, but both products are identical, the organic products consistently get higher ratings for taste, nutritional content and a willingness to pay more, showing we are influenced by the organic label.
On the positive side though, organic produce is not allowed to have pesticides or herbicides which although stated as safe in the dosages applied to crops, there are still concerns with accumulation over time and the rise of pesticide/herbicide resistant insects/weeds. Organic economy - In LEDC’s (Less economically developed countries), organic farming can have positives and negatives. Very simply, organic farming is labour intensive compared to commercial agriculture using synthetic fertiliser. This presents an opportunity for these farmers to create jobs and employment in areas that desperately need it. However, some farmers cannot afford to create these jobs and therefore have to work harder which can be unsustainable and in the worst scenarios, put them out of work. Because of the growing ‘organic food is healthier’ trend in western society, traditional agriculture prices are falling and making it harder for farmers to profit, which makes it harder to look after their families if they cannot maintain growing crops organically. Furthermore, without the use of pesticides, there’s a very real danger of losing entire crops to pest and disease, an economical nightmare.
To go a little deeper, we could look at something called atom economy, does the amount of organics that we have to use on crops work out economically on an atomic scale. Synthetically produced fertilisers are atomically economical and therefore better for sustainability in certain cases.
Another concept that we can apply is the E-factor, the ratio in a mass of product produced to the waste produced. Synthetically produced fertiliser wins again, with a low waste to product ratio against organic which has a high waste to product ratio.
Growing organically indoors: If you’re an advocate for organics and you grow to utilise indoor gardening, then the likely opinion for doing so is better taste, better quality produce and no chance of PGR’s which in some instances are undesirable. I would argue that the reason indoor grown organic produce apparently tastes better, is because of the compensation for mistakes organics/soil affords you. A buffer against big swings in pH allows continual nutrient uptake compared to most mineral based nutrients, the use of beneficial microorganisms is essential in an organic garden and this alone will improve quality, along with the fact that growing organically it is much harder to over fertilise which can give a chemical taste to your product.
Is it really the organic fertiliser that makes it taste better with higher quality or is it just because we believe growing organically is better (cognitive bias)? Is it that usually people growing organically tend to spend more time and give more effort to growing plants than the typical mineral grower or is it because, like we mentioned above, it’s harder to over fertilise with organics which makes the plant potentially healthier at harvest? These are questions that need answering scientifically, up to now there is no evidence of better taste and minimal evidence of better quality (nutrition status). If plants could talk, would they be able to tell you the difference between a mineral based ion and an organically derived ion? At this moment in time, there are no scientists in the world that could differentiate between either the organically produced ion or the synthetic ion. Something to bear in mind when making an argument for or against organics. Lastly, anyone growing organically reading this, I am not against growing organically, the main reason for doing so, in my opinion, would be to make sure that the final product is as clean as possible. If it has been organically certified then it will not have plant growth regulators (PGR’s). A lot of PGR’s are perfectly safe and enhance plant health, some are bad (Paclobutrazol and Daminozide), therefore I would not be 100% confident that mineral-based fertilisers are free from these PGR’s. One of my current research projects is investigating mineral hydroponic fertilisers to see what PGR’s they contain.
My opinion on the quote at the top of the page is that although it makes us realise that to go completely organic is not feasible in our current agricultural and political climate, it’s also a very pessimistic view to take. We don’t have a food crisis, we have a food distribution crisis and if you’ve read my previous articles on food policy, you might remember that we waste literally thousands of tonnes of food which is perfectly edible. So if we solve the food distribution crisis, can we look at making organic agriculture the normality and the traditional synthetic fertiliser agriculture a historical memory? Do we have the space to grow organically (which requires more land) in an increasingly urban environment? Will the people who profit from the traditional agricultural industry allow this to happen easily?
There are always two sides to every coin and we need to look deeper into all issues before we take a strong stance for or against organic produce. Hopefully, this article has stimulated some thoughts on the organic vs synthetic debate and entices you to research further on the subject.
Thank you for reading,
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Stephen Brookes - NPK Technology
Organically derived microbial inoculant that allows the plant to uptake much more Phosphorus. Think of it as having to eat a roast dinner, how much time and effort does it take to cut, chew and digest your food… That’s your current phosphorus uptake (if you’re an organic grower, you have to cook the roast dinner first as well).
With Mammoth P, the microbes are the metaphorical ‘blenders’ in the kitchen, throw in the roast dinner, blend it up and see how much easier it is to take the roast dinner now!
Why do you even want as much Phosphorus in the plant anyway?
To get nerdy for just a second, there’s a biochemical in humans and plants called ATP. It’s the currency of energy, like pounds and dollars for money. The more ATP we can produce, the more energy we will have and also the more energy your plants will have.
ATP stands for Adenosine TriPhosphate! That’s three phosphates! More phosphorus gives the plant the ability to generate more energy…
What’s it going to do with all that energy?
- Stimulated root development
- Increased stalk and stem strength
- Improved flower formation and seed production
- More uniform and earlier crop maturity
- Increased nitrogen N-fixing capacity of legumes
- Improvements in crop quality
- Increased resistance to plant diseases
- Supports development throughout entire life cycle
If you want to give your plants more energy, Mammoth P is the way forward. It can be added on top of your current grow schedule and guarantees better results!Check out the products here and thanks for reading!
Check out the products here and thanks for reading!
WEEK | GROWTH STAGE | SOIL (ml/Litre) | HYDRO (ml/Litre) |
---|---|---|---|
1 | Seedling/clone | 0.16 | 0.16 |
2 | Seedling/clone | 0.16 | 0.16 |
3 | Growth | 0.16 | 0.16 |
4 | Growth | 0.16 | 0.16 |
5 | Aggressive Growth | 0.26 | 0.16 |
6 | Aggressive Growth | 0.26 | 0.16 |
WEEK | GROWTH STAGE | SOIL (ml/Litre) | HYDRO (ml/Litre) |
---|---|---|---|
1 | Transition | 0.4 | 0.16 |
2 | Bloom | 0.4 | 0.16 |
3 | Bloom | 0.66 | 0.16 |
4 | Aggressive Bloom | 0.66 | 0.16 |
5 | Aggressive Bloom | 0.66 | 0.16 |
6 | Aggressive Bloom | 1.06 | 0.16 |
7 | Aggressive Bloom | 1.06 | 0.16 |
8 | Flush | 0.26 | 0.16 |
9 | Flush | 0.26 | 0.16 |
Stephen
NPK Technology
A 'New Age Nutrient Order'?
There has been a lot of research on nano particles over the last 16 years, but only recently (2008) has there been research on nano particles and the influence on plants, something we will refer to as Phytonanotechnology. Questions such as the following will be looked at;
What benefits will phytonanotechnology have?
Will there be negative associations such as bioaccumulation?
What impact will phytonanotechnology have on the environment?
What is the future for phytonanotechnology?
These are some of the questions we aim to answer in this article because with a relatively new technology, these types of concerns are often raised, but we shouldn't let these innate concerns cloud judgement, so we're going to let the science do the talking instead.
Introduction:
Nanoparticles are particles that are anywhere between 1 and 100 nanometers in size. To give this some comparison, you could fit 1 million nanoparticles (1nm) into this full stop here. A typical nanoparticle of fertiliser will be between 10-20 nm so you could fit between 50,000 and 100,000 nanoparticles of this size into this full stop. You could also fit 100,000 nanoparticles into the width of a human hair... Nano particles are incredibly small and it's a small miracle that we have learnt to manipulate and adapt them to cover a wide range of beneficial products. The reason they offer exciting advances in horticulture as well as other industries is because at the nano level, molecules will act differently to their larger bulky counterparts and have unique physiochemical properties such as smaller size, chemical composition, surface structure, stability and shape.
Some of the areas that nanoparticles are currently used include; Automobiles (made lighter), clothing (Stain resistance), Sunscreen (Increased UV protection), surgery (Synthetic bones made stronger), mobile phones (Lighter materials), glass packaging for drinks (Longer shelf life) and in sports (durable equipment such as tennis and golf balls).
What are they doing in horticulture though?
The research in horticulture has been varied and consistent over the past 8 years, the main nano particles being tested for horticultural viability include Iron (Fe3O4), Silica (SiO2), Cobalt ferrite (CoFe2O4), Titanium oxide (TiO2), Zinc oxide (ZnO), Copper oxide (CuO) along with gold and silver nanoparticles (Au and Ag). There are many more being investigated but those were the elements with the most amount of research around them.
Iron (Fe3O4) has had a lot of research recently, one study by Zhu et al. (2008), showed that the nanoparticles are directly taken up and translocated in pumpkin (Curcurbita maxima) with no toxic effects at concentrations of 0.5g/l (1).
Silica (SiO2) has had good work done by Slomberg (2012) showing silica nanoparticle phytotoxicity to Arabidopsis thaliana, a popular plant model for plant biology and genetics, no toxicity was found at doses of 1000mg/l (2).
Phytonanotechnology advances and advantages
The benefits of phytonanotechnology are wide and varied according to the research that's been conducted so far. Phytonanotechnology can deliver fertilisers, pesticides and herbicides to targeted sites and be released on-demand for nutritional needs or pest protection, this would reduce the requirement for repeated application of fertiliser/pesticide/herbicide and therefore reduce the negative affects on the environment. A recent review of nanotechnologies in plant sciences by Wang et el. (2016) says that phytonanotechnology can;
1) Reduce applications of plant-protection products
2) Decrease nutrient losses from fertilisers
3) Increase yields through optimised nutrient management (3).
The most important aspect for commercial growers is the increased yield due to the lower energy required by the plant to uptake nutrients. The nanoparticles are so small they require very little to no energy from the plant via active transport to pull the nutrients into the vascular system, the plant therefore has more energy for other processes such as fruit/root/flower formation and production.
One of the benefits with nano Iron (Fe3O4) through leaf tissue analysis was the increased uptake of other nutrients when using nanoparticles. The reason is thought to be because of the increased chlorophyll production in the leaf which increases the amount of light harvested and therefore the bigger nutrient requirement, the leaf tissue analysis saw an increase of Nitrogen, Phosphorous, Potassium, Calcium, Magnesium and other micro elements compared to a control without nanoparticles.
Observational studies have shown an increase in oil production in the tobacco plant when using Iron (Fe3O4), although this needs further testing and analysis to confirm findings. Over the coming years, there will undoubtedly be a plethora of benefits coming from phytonanotechnology, but there are concerns over the effect to the environment and the living species within it.
Phytonanotechnology concerns
One of the concerns about phytonanotechnology is the effect of bioaccumulation in plant material being passed to herbivores, insects, birds and carnivorous animals. If the nanoparticles accumulated and were eventually consumed by humans, what impact would this have on the food chain and humans' health?
This question has been looked at by numerous studies (4, 5, 6 and 7), the nano particles studies were Au (gold), CeO2 (Cerium Oxide) and La2O3 (Lanthanum oxide). What the studies show is that although they did not find biomagnification of nanoparticles there was some trophic transfer, therefore human exposure to nanoparticles via food dietary uptake or food chain contamination needs to be considered when these phytonanotechnologies are developed. This trophic transfer is very good news when developing nano particles to correct deficiencies such as iron deficiency anaemia, but also shows we need to be careful about what nanoparticles are used and how much research has been conducted before using them.
The environment
Research by Scherzinger (2008) (8), said in an article that, in essence, current nanoparticles pose very little risk to the environment, possible problematic nanoparticles require further research but ultimately to make a defined statement we need to assess all nanoparticles as they will have different effects depending on size, composition and surface treatment. The current phytonanotechnology research and product availability is on Iron and Silicon, Fe3O4 and SiO2 respectively. Due to their source material coming from natural sources, there will be no detrimental effects to ecosystems and the natural environment. However, future phytonanotechnology may require more research and testing before being used in agriculture or hydroponics.
The future of phytonanotechnology
The future for nano technology in horticulture is promising, it can present revolutionary ways of increasing crop yield, health and human nutrition along with safer methods of applying pesticides and herbicides. As a relatively new technology though, researchers and scientists must look further into toxicity and trophic transfer of nano particles, in environments that are similar to those that they will be used in, to establish wide acceptance by the public and to reduce the innate fear that people can have with new technologies such as this. To conclude on a positive note, current research on potato’s have shown dramatic increases of nano Iron, Calcium and Zinc in potatoes. This could potentially lead to reductions in diseases such as iron-deficiency anaemia in lower economically developed countries.
The future for nano technology in horticulture (phytonanotechnology) is extremely promising and we’ll hopefully be looking back at this article in a couple of years time with a whole host of innovate nano products… Time will tell.
Visit this website for current Nano technology product for Hydroponics and horticulture.
www.nanohydroponics.co.uk
References:
(1) Zhou, H. et al. (2008) Uptake, translocation, and accumulation of manufactured iron oxide nanoparticles by pumpkin plants. J. Environ. Monet. 10, 713-717
(2) Slomberg, D.L and Schoenfisch, M.H. (2012) Silica nanoparticle phytotoxicity to Arabidopsis thaliana. Environ. Sci. Technol. 46, 10247-10254
(3) Wang, P. et al. (2016) Nanotechnology: A new opportunity in plant sciences. Trends in plant science. TRPLSC. 1423, 1-14
(4) Judy, J.D et al. (2012) Bioaccumulation of gold nano materials by manduca sexta through dietary uptake of surface contaminated plant tissue. Environ. Sci. Techno. 46, 12672-12678
(5) Unrine, J.M et al (2012) Trophic transfer of Au nanoparticles from soil along a simulated terrestrial food chain. Environ. Sri. Techno. 46, 9753-9760
(6) Hawthorne, J. et al. (2014) Particle-size dependant accumulation and trophic transfer of cerium oxide through a terrestrial food chain. Environ. Sci. Technol. 48, 13102-13109
(7) De la Torre Roche, R. et al. (2015) Terrestrial trophic transfer of bulk and nanoparticle La2O3 does not depend on particle size. Environ. Sci. Technol. 49, 11866-11874
(8) Scherzinger, M. (2008) Nanoecotoxicology: environmental risks of nanomaterials. Nat. Nanotechnol. 3, 322-323
]]>England and all civilised nations stand in deadly peril of not having enough to eat. As mouths multiply, food resources dwindle. Land is a limited quantity, and the land that will grow wheat is absolutely dependent on difficult and capricious natural phenomena... I hope to point a way out of the colossal dilemma. It is the chemist who must come to the rescue of the threatened communities. It is through the laboratory that starvation may ultimately be turned into plenty... The fixation of atmospheric nitrogen is one of the great discoveries, awaiting the genius of chemists.
Sir William Crookes – 1898
The “genius of chemists”, was the German Fritz Haber, who discovered how to artificially fix Nitrogen (N) along with the industrial engineer Carl Bosch who scaled up the process so it could be accomplished on an industrial scale. The process came to be known as the Haber-Bosch process, this process produces over half a billion tons of artificial manure every year, requiring a huge 5% of the world’s natural gas to do so. The Haber-Bosch process sustains more than a third of the worlds food production, so it transpired that Sir William Crookes was absolutely right in his prediction on the importance of Nitrogen fixation in the agriculture industry.
Nitrogen
The 7th element of the periodic table, it is an odourless, colourless, and mostly inert gas, and continues to be colourless and odourless at a liquid state. Nitrogen makes up around 78% of the air you breathe and is present in all living things, including the human body and plants.
The importance of Nitrogen
Nitrogen is found in both organic and inorganic forms in the plant. It combines with Carbon, Hydrogen and Oxygen (sometimes with Sulphur) to form amino acids, amino enzymes, nucleic acids, chlorophyll, alkaloids and purine bases. To emphasise the importance here, amino acids are the structural building blocks of proteins, so without Nitrogen there are no amino acids and no amino acids means no life. Furthermore, Nitrogen has an essential role as a base element for nucleotide molecules, the building blocks of DNA and RNA, which are the blueprints and translators of the genetic code respectively. Lastly, without the 4 Nitrogen atoms in the chlorophyll molecule (C55H72MgN4O5), there would be no photosynthesis. This also helps to explain why a Nitrogen deficient plant turns yellow, due to the lack of chlorophyll’s green pigment… Nitrogen is kind of important when growing plants.
Nitrogen and metabolism
Plants absorb Nitrogen as either NO3- (Nitrate) or NH4+ (Ammonium) ions. Both of these ions supply Nitrogen to the plant, but they will have big differences within the plants metabolic pathways. Nitrate for example is absorbed by the plant slowly and as we mentioned before provides the materials needed for the production of amino acids and other structures. In comparison, ammonia is absorbed rapidly and can cause problems such as toxicity if present in high concentrations.
The uptake of NO3- stimulates the uptake of cations (Positively charged ions), however chloride (Cl-) and hydroxyl (OH-) anions (Negatively charged ions) restrict NO3- anion uptake. This could be an explanation for why some cultivators choose to let their water stand for 24 hours before watering, which allows the chlorine to evaporate off. This practice has not been scientifically proven to give the cultivator any apparent benefits other than the water reaching room temperature to reduce shock from cold/hot watering.
Spotting Nitrogen deficiency and over fertilisation
A typical Nitrogen deficiency will manifest itself within the plant as a pale green coloring on the lower leaves, moving upwards through the plant as the deficiency becomes worse, eventually turning brown and dying. Plant growth is slow and maturation occurs earlier than normal with possible stunted growth. Nitrogen is a highly mobile element within a plant, therefore when a deficiency does occur, Nitrogen can translocate to the parts of the plant that require it the most, i.e. the new shoots and younger parts of the plant. This explains why yellowing occurs from the bottom upwards.
It should be worth noting that overwatering can also look like Nitrogen deficiency to an un-trained eye, as it also manifests itself as a yellowing of the plant, the cause of this is a lack of oxygen at the root system.
Nitrogen excess makes the leaves a very dark green colour, any new growth will be succulent and the plant is very susceptible to disease, insect infestation and drought stress. Lodging, blossom end rot (BER) and lack of fruit set can often occur as well.
The importance of Nitrogen cannot be understated, it is a fundamental part of the growth and an important part of the flowering stages in a plants life cycle. However, with a good nutrient formulation and sound cultivation practice, it should be a very rare occurrence that a Nitrogen deficiency or excess occurs in the grow room.
Thanks for reading the second installment of ‘What is…’, hopefully I’ve added a little insight into the 5th most abundant element in the universe.
NPK Technology
]]>“The biochemistry of Silicon in planta is a riddle, wrapped in a mystery inside an enigma” (Epstein, 2001).
Silicon is still today not as well understood as many of the other elements that we commonly use in our plant feeding regimes, it’s probably not used as widely as other additives and yet it is (in my opinion) one of the most important tools in a grower’s arsenal. I say this because of what it can do for your plants throughout all stages of growth and reproduction, which varies from helping the plant to support itself through stronger cell walls, preventing pests from making their homes on your petunias, stopping disease in its tracks and allowing plants to survive in very hot/cold conditions. If you don’t currently use a Silicon product, get it on your shopping list for the next time you’re at the grow shop and enjoy the sense of calm that this product will afford you.
Here’s the science…
Plant roots take up Silicon, chemical symbol ‘Si’, in the form of silicic acid (Si(OH)4), it is then transported from the roots to the shoots via the xylem and distributed around the plant organs depending on transpiration rates of each plant organ. The epidermal cell walls are impregnated with a layer of Si and become effective barriers against water loss by cuticle transpiration and fungal infections.
There are two hypotheses for how Silicon protects a plant, the first one says that the Si acts as a physical barrier, the Si is deposited beneath the cuticle to form a Cuticle-Si double layer and protects the plant mechanically by withstanding pest and disease penetration into the leaf. The other method says that plants supplied with Si produces phenolics, lignin, H2O2 and phytoalexins in response to fungal infection.
Silicon alleviates various abiotic stresses including physical stress (Drought, radiation, high and low temperatures and freezing) and chemical stress (Salt, metal toxicity and nutrient imbalance). Si relieves water stress by decreasing transpiration, as this mainly occurs through the stomata and partly through the cuticle, Si deposited below the cuticle may decrease any losses.
Lastly, Silicon is not a mobile element, so any deficiencies will show up on younger leaves. It is not classed as an essential nutrient as a plant can grow and reproduce without it, but for many gardeners including myself it is a crucial part of my feeding regime.
Silicon in the grow room…
I know some of you reading this may think, “I’ve never used Silicon before and I’m doing great”, but that’s just like saying “I built a house from just bricks and mud and it looks good to me”. Well if you added cement to those bricks, you could have a bigger house and one that’s going to stay up a lot longer. Silicon is the cement in that metaphor and including it will give your plant extra support, improved growth, and bigger yields.
There are a lot of silicon products on the market and some companies say that their Silicon product does not affect pH as dramatically as others, this is a marketing trick and although it’s true what they say, it’s because they have likely watered down the silica so it’s effect on pH is not as drastic. Don’t be fooled by creative marketing.
Lastly, the method of adding the silica to the nutrient tank is very important. Here’s what you should be doing to prevent the solution from becoming cloudy which means the silica has precipitated out of the solution and become less available to the plant. Firstly, add the silica to you water tank and measure pH, next step is to reduce the pH to 7 and add the rest of your nutrients, lastly adjust pH to desired range depending on the type of plant being grown, this is typically between 5.8 and 6.3. This method although time consuming is best practice for getting the most out of your plants whilst using silica.
I hope this first article in the ‘What is…’ range has been beneficial to you and also that you feel that Silica is an additive worth adding to your feeding regime, I can tell you with good authority that it definitely isn’t a Silly-Con…
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What is humidity?
You know those really hot days, when no matter what we do we just can’t cool ourselves down… that’s mainly due to high humidity! When the air around us is saturated with water vapour, we cannot cool ourselves, as the sweat from our skin can’t evaporate. Then we have the really hot days that we could just lay in the sun all day but stay relatively cool… That’s due to low humidity! The air is quite dry and allows any perspiration to evaporate off of our skin and keep us cool. However, extremely low humidity (25% and below) can have detrimental effects on us humans, such as dry skin, irritated eyes and respiratory system. The funny thing is that it’s the same for plants. Humidity is one of the most underrated environmental aspects of an indoor garden and it’s definitely something we need to keep an eye on.
Before we get technical with relative humidity and why it’s essential to monitor and control it, the essence of the article is that we want to avoid extremes. A good humidity range during vegetative growth is around 60-70%, this is because before a good root system has formed, the plant will find it easier to maintain equilibrium of water uptake and water loss. During the flowering stages it is good practise to drop the humidity to 40-50% to prevent any mould or pathogens from forming, but it also ensures good movement of water, nutrients and minerals through the plant to the flowers or fruits. Cuttings are special and require a humidity of 90% to form new roots, whilst seedlings do well at around 60%. That’s the essential bit of information that we all need to know, so we can now delve a little deeper into the technicalities of humidity.
Key words:
Transpiration: The rate at which the plant expels and absorbs moisture, helping to cool the plant and enabling a flow of water, nutrients and minerals.
Stomata: These are the pores that regulate moisture within the plant; they help protect it from dramatic changes in moisture.
Saturation: When a gas (or a space) holds the maximum water vapour possible at a given temperature, it is said to be saturated. If extra water is added to a saturated gas, or if its temperature is reduced, some of the water vapour will condense.
Osmosis: The movement of water (Solvent) molecules across a semi-permeable membrane from a region of a relatively low concentration of dissolved substances (solutes) to a region of relatively high concentration of solutes.
Relative humidity (RH): It is the ratio of actual water vapour content to the saturated water vapour content at a given temperature and pressure expressed as a percentage (%).
The air temperature is vital to know when measuring relative humidity. This is because, the ‘relative’ part is essentially relative to the temperature and how saturated the air is at its current temperature. For example, if your grow room rises in temperature, the relative humidity will drop, so at a RH of 50%, a temperature rise from 20°C to 21°C will cause RH to drop by about 3%. The digital thermometer that you should be buying from the local grow shop, usually comes paired with a humidistat, it’s an essential piece of equipment to say the least.
To understand how plants operate under different humidity’s we need to understand how a plant works. All plants allow carbon dioxide (CO2) to enter through their leaves via tiny openings called stomata; this gas is used in photosynthesis. The plant regulates it’s intake of CO2 by opening and closing its stomata and as it does this, moisture in the leaf can escape. If our grow room is dry (low humidity), it causes the plants to transpire much more rapidly than in an environment with a higher humidity. When this happens, the leaves become flaccid and begin to wilt, over a longer period of time the plant will close its stomata and reduce the flow of water out of the plant, this is very effective at stopping water loss but unfortunately it also reduces the intake of CO2; without an adequate supply of CO2 the cells will begin to die and the plant will look tired and ill. The key point to remember here is that dry air will remove water from the leaves quicker than the roots can deliver it, under these conditions it doesn’t matter how much you water the plant, it won’t help and overwatering will remove oxygen from the root zone (rhizosphere), creating further problems.
When a plant has the right humidity for its stage of growth it will thrive, the stomata will open completely and the plant will enjoy a good fresh supply of CO2, with controlled water loss from the leaves.
This loss of water from the plant to the atmosphere is known as evapo-transpiration. This loss of water is regulated by the opening and closing of guard cells, but also something called the vapour pressure gradient which is the difference between the water vapour content of the atmosphere and the vapour pressure within the sub-stomatal cavity. The reason this is important is because it brings me to my next point which is air movement around your plants. A layer of saturated or partly saturated air will now have built up around the leaf if the air is still. Slight air movement will move this saturated air away and helps in the cooling of the leaves because of the transfer of heat by convection from the leaf surface. This movement of water away from the plant allows more water molecules to move through the plants veins, the stem and the roots, creating a negative water pressure in the root zone which allows the plant to ‘drink’; this process is known as osmosis. An important point to note though is that high wind velocity from clip fans will move all of the air away from the leaf boundary and result in a dry atmosphere which increases water loss, something we don’t want too much of during vegetative growth. Therefore we want our clip fans on the lowest setting and we don’t want them pointing directly at the plants, somewhere between the tops of the plant and below the lights is the golden zone.
After all of that information, it may be difficult to know where to start, here’s some top tips.
As we said at the start of the article, plants, just like humans like environmental stability in their lives. Whether it’s relative humidity or temperature swings, prevent dramatic changes in short spaces of time and your plants will metaphorically thank you.
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Firstly, we should all be using an EC pen to measure the amount of fertilizer in our water, an EC pen or truncheon (EC stands for Electrical conductivity) will measure the amount of salts in the water which you add as fertilizer (Fertilizers are salts). The more fertilizer you add, the greater the EC.
Now think of your plant as a very quickly growing person, when it's young it doesn't want a lot to eat so we set our EC at roughly 0.5 -0.8, then as the plant matures through late veg and early flower we would like an EC of around 1.0 - 1.4. During peak flowering (Adulthood) we will increase our EC to 2.2 maximum (depending on how the plant is feeding), from then on it is recommended to reduce your EC or amount of fertilizer as the plant's metabolism starts to slow (think of this like an old person who eats much less as they get older). This will help you if you flush your plants at the end.
This type of plant centred feeding is much better and more cost effective over the long run than giving your plants the same feed throughout its life. You should think of your EC meter as a speedometer, without one how will you know how fast you are going, similarly without an EC pen, how do you know how much your plant is taking up? In our opinion, an EC pen should be your next priority if you don't have one.
To finish off, when you start using an EC pen, you will be able to more accurately feed your plants, measure runoff concentration during a periodic flush and have better control over how your plant grows.
We highly recommend Bluelab for accuracy and the 2 year guarantee they offer on all products. (http://www.npktechnology.co.uk/products/bluelab-ec-pen)
Hope this has been helpful, please comment with any questions if you have any below.
The NPK team
]]>Professor Dickson Despommier thinks the answer is literally in the sky and has developed the Vertical Farm, i.e. high-rise agricultural structures to feed urban areas.
Based on Despommier’s ideas, the design group Aprilli has created the Urban Skyfarm concept, which is planned to be built in downtown Seoul.
Korea’s capital city runs along the Cheonggyechon stream, meaning it has a steady supply of water that can be used to water the tree-like structure. Each of its components—root, trunk, branch and leaves—has its own structural characteristics and is suitable for different farming conditions. Users can plant various types of vegetables and fruits, including leafy greens, root vegies and even apple trees.
Skyfarm will use hydroponic farming and will receive supplementary heating and lightning. It will use mostly renewable energy produced on site and will also have public spaces, including a farmers' market.
“Together with the Cheonggyecheon stream, the Urban Skyfarm will become a nice destination place for people seeking for fresh food, air and relaxation within their busy urban life,” explain their creators in their project abstract.
Suddenly the future of megacities doesn’t look so bleak!
Thanks for reading,
NPK technology
]]>Instagram: @NPK_Hydroponics to DM us and see regular top tip updates!
Imagine the first juicy bite of a perfectly ripened, locally grown, fresh summer tomato. Now, imagine foregoing those grainy, artificially ripened tomatoes from the grocery store and enjoying the unmatched goodness of homegrown tomatoes all year round. You can make that dream a reality by growing hydroponic tomatoes right in your own home. Growing tomatoes hydroponically allows you to monitor and control the lighting, temperature, and nutrients that the plants receive, thus controlling the flavour, sweetness, and nutritional value produced by the plants. Even the extreme novice can successfully produce fresh, succulent tomatoes with a little background information and technique tips.
It is highly recommended, to begin with seeds rather than plants as plants can be contaminated with disease or pests. Rockwool starter cubes and standard dome nursery trays are a great start. Soak the rockwool cubes in water with a pH of 4.5. Plant the seeds. Keep trays covered and in a damp setting that remains consistently between 20 and 25 degrees Celsius (68°-77°F) until the plants start to sprout. As soon as vegetation shows, the seedlings should be moved to a light source for a minimum of 12 hours each day. Make sure that the roots never gain light exposure as this can stunt growth and even kill the roots completely. When leaves have sprouted and the roots are visible at the bottom of the rockwool cubes, the plants can move into their new hydroponic home.
Choosing the right hydroponic grow system depends on space availability, the type of tomato, and the size of the plants. Deep water culture (DWC) is most often used for the cultivation of only a few plants as it is fairly tedious to maintain. Generally, in a DWC system, one plant is grown per pot. A clay pebble growing medium is used. The water and nutrient mixture must start out at a high enough level to saturate the clay. After the root system is established, the water level should be lowered so that most of the roots are well into the water, but so that a few are in the empty space between the water level and the container. An air stone is used to aerate and mix the nutrient-rich water and should always run 24 hours a day. The pH in this type of system tends to naturally fluctuate, so it should continuously be monitored.
If you have not had much experience with hydroponics, the nutrient film technique (NFT) may be the setup that you most recognize. Consisting of only a grow tray or tube, a nutrient reservoir, an air pump and stone, and a nutrient pump, it needs no timer and no growing medium. The nutrient pump carries the solution to the grow tube. The plants are usually contained in baskets and the roots dangle directly into the solution. The solution flows down the tube and back into the continuously aerated reservoir. The roots will dry out very quickly if the flow of nutrients is broken, so this type of system leaves the plants extremely susceptible to pump malfunctions or power outages.
For larger plant systems and commercial growing, a drip irrigation system is often used. In this type of system, a nutrient solution is pumped through an automated system that drips the solution onto the plants and re-circulates it. Plants and starter cubes are placed directly into individual pots that are each connected to the nutrient reservoir and haydite rocks are used to sufficiently aerate roots in a confined space.
Aeroponics is perhaps the most sophisticated technology. In an aeroponic system, the root systems are suspended in the air above the nutrient solution. The nutrient pump is controlled by a timer that periodically mists the roots with the solution. The timing and proper functioning of the pump are critical. There is little room for error using this method of hydroponics as clogged sprayers and pump failures can ruin a crop very quickly. It should also be noted that, to my knowledge, there are no large-scale commercially grown aeroponic tomatoes.
The water quality and the nutrient solution are the key factors to successful hydroponic tomato cultivation. The pH of the water should remain between 5.0 and 7.0 at all times for optimal nutrient absorption. The pH of the nutrient solution should be between 5.5 and 6.0. The electrical conductivity of the water should be less than 0.5 mS/cm.
The concentration of the nutrient solution must be adjusted at various stages throughout the growth cycle. The essential nutrients are divided into macro and micro elements. The macro elements (required at higher concentrations) are calcium, carbon, hydrogen, magnesium, nitrogen, oxygen, phosphorus, potassium, and sulfur. The micro elements are boron, chlorine, copper, iron, manganese, and molybdenum. Essential concentrations are measured in parts per million (ppm) or milligrams per liter (mg/L). Tomatoes require a relatively low nitrogen level compared to leaf crops and root crops. The required micro element levels for tomatoes are as follows: boron 0.44, chlorine 0.85, copper 0.05, iron 2.5, manganese 0.62, molybdenum 0.06, and zinc 0.09 ppm. The necessary concentration of macro elements changes after the plants reach about 24 inches tall and the fruit reaches about 1 to 1.5 cm in diameter. More nitrogen is needed in summer months or during times of higher light exposure, and more potassium is needed in the fall and winter months.
Nutrient deficiencies can cause a whole host of unwanted effects on the plants and adversely affect the crop’s fruit yield. pH levels that are too high result in hindered nutrient absorption. pH levels that are too low allow excessive absorption. Maintaining optimal lighting and temperature ranges create the best environment for healthy, high-yield plants. Some disorders may not show any visible signs right away or at all, so it is very important to ensure that your nutrient solution is properly maintained. Deficiencies can cause varying degrees of problems from delayed maturity, small fruit, curling and yellowed leaves to limited fruit yields and aborted flowers.
Light is the most important growth influencing factor. During the vegetative stage, plants produce a healthy supply of leafy vegetation that will later go on to feed and support the product yielded during their flowering stage. When starting a tomato seed, you can supply 24 hour light through to early vegetative stage. During the vegetative state, mature tomato plants thrive on 16 to 18 of direct light per day and eight hours of darkness for respiration.
LED grow lights are becoming increasingly popular to grow hydroponic tomatoes. They emit a powerfully mixed spectrum of light that uses 1/3rd to 1/2 the energy compared to HID lighting. They also produce a minimal amount of heat, so they can safely be placed as close as within 30 cm of the plants. Plants respond more vigorously to the clean, cool, intense light emitted by LED grow lights, experiencing increased growth rates over HID so be sure to keep an eye on your nutrients.
Maintaining the architectural structure of the plants as they grow larger and begin to produce higher fruit yields keeps the plants strong and optimally feeding the fruit produced. You can use plastic twine to encourage a straight vertical growing path and to support the structure as it produces heavy fruit. Lateral side shoots and suckers should be removed. Gently break off suckers with your hands to avoid damaging or contaminating the plant. If the top of the plant dies, leave one strong lateral shoot to grow into the new leading shoot. Remove yellowed leaves at the main stem to avoid the risk of disease and infection.
Patience and practice will ultimately lead you to a successful hydroponic tomato crop. Carefully balancing nutrients, aeration, pH levels, temperature, and lighting and misting schedules is a delicate process that takes some getting used to in order to get the greatest flavour, size, and quantity out of your produce. As you gain experience with recognizing potential issues and adjusting settings, you will no doubt learn to produce beautiful, delicious, vine-ripened tomatoes year round.
NPK Technology]]>This season, NPK Technology are taking part in a feature in Episode 2, where they go head to head with Gro Supplies in Newcastle, to see who can build the best 1.2m tent system, no expense spared. You can catch every Episode on SKY channel 192 and FREESAT 402. Episode One airs on Monday 11th November at 9pm, and continues for six weeks, with repeats on Sundays at 6:30pm. You can also catchup on missed episodes on YouTube directly after Monday's live broadcast.
Visit the HydroShow YouTube Channel, Website,or Facebook page for more information
www.youtube.com/hydroshowtv | www.hydroshow.tv | www.facebook.com/hydroshow
If you want to improve your grow room skills and hydroponic garden, HYDROSHOW 1.1 is the place for you.
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