Fertiliser
All Purpose Fertiliser 4-4-4
True all-purpose 4-4-4 for veg, fruit, flowers and containers.
from £12.00
Customer highlight
I’ve literally written a book about these guys products! Every single thing I’ve tried is amazing and this one is no different!! I use as a folia spray and a soil drench. The L-amino is the amino u want to have and the fulvic/humic is great too stop nutritiant lock out. As it holds ions locking together but lose enough it can be used:) so if you’re feeding heavy it’s a must. It does have a smell but it doesn’t last for long. I wouldn’t say it’s an unpleasant smell. Like fermenting smell
Editorial highlight from marketplace and store reviews — separate from the full review list below.
Liquid amino acids: a plant-based foliar biostimulant with 40% amino acids and 5.78% nitrogen
40% Total Amino Acids 28.27% Free Amino Acids 5.78% Nitrogen Foliar Specialist Plant-Based, Vegan-Friendly Packed in Stockport
Quicker green-up and better recovery after frost, drought or heat, from a spray of ready-made amino acids. Plants normally build every amino acid themselves from nitrate or ammonium. Spraying the finished amino acids on the leaf hands them the parts ready-made, and the 5.78% nitrogen adds a small, fast top-up.
The liquid carries 40% total amino acids (400 g/L), 28.27% free amino acids (282.7 g/L) that a leaf can take up as they are, and 5.78% nitrogen. The amino acids come from plant protein broken down by enzymes, which keeps them in the form a plant can use, at pH 4.5–5.5 for foliar work. Plant-based, packed in Stockport.
Shake, measure 3 ml per litre and spray every 10–14 days on anything with leaves, or 4 ml per litre after a stress event. Keep a base fertiliser in place for nitrogen, and keep watering: it works alongside both. For drenches, seed soaks and fertigation, use the Organic Amino Acid Fertiliser powder; the two are compared below.
40%Total amino acids
28.27%Free amino acids
5.78%Nitrogen (N)
pH 4.5–5.5Foliar-ready acidity
What liquid amino acids are used for in the garden
- Routine foliar biostimulant: 3 ml per litre every 10–14 days through the season on anything with leaves; the amino acids go in through the leaf
- Recovery after frost, hail, drought or heat: a stressed plant still needs protein to repair itself and is poorly placed to make it; a 4 ml per litre spray supplies the building blocks direct
- Quick nitrogen correction: at 10 ml per litre the 5.78% nitrogen arrives as amino acids, for pale or yellowing lower leaves
- Lawns: 3 ml per litre through a sprayer or a rosed watering can for green-up and recovery after wear, drought or a hard scalp
Liquid amino acids or the amino acid powder: which one?
Liquid Amino Acid Biostimulant (this product)
- 40% total amino acids, 28.27% free, 5.78% nitrogen
- Built for the leaf: liquid, pH 4.5–5.5, nearly nine-tenths of the amino acids already free
- For frequent, dilute foliar sprays, stress recovery and nitrogen correction
- Plant protein, enzymatic hydrolysis, no animal by-products
Organic Amino Acid Fertiliser (powder, 13-0.3-8)
- 84.8% total amino acids, about 2.1 times the concentration of the liquid
- 13% nitrogen, 8% potassium (K₂O) and 3,000 ppm amino-chelated iron
- Water-soluble micro-granules for foliar spray, soil drench, fertigation and seed soak
- Lower rates per litre, and the one to pick for iron chlorosis or root-zone feeding
- Best dissolved in a little warm water first, then diluted
Short version: liquid for the sprayer, powder for everything else. The longer argument for amino acids, and which type to buy, is in Amino acid biostimulants: what actually works.
Packed in Stockport
Bottled and labelled in small batches in Stockport. A plant-based, vegan-friendly biostimulant with the amino acid content printed on the label. Part of the Dr Forest biostimulant range.
The Science
The science of liquid amino acids: why a foliar spray of ready-made building blocks works
What a liquid amino acid biostimulant is
Proteins are chains of amino acids. Cut a plant protein back into its units and you have a protein hydrolysate: a mix of free amino acids and short peptides. How it is cut matters. Colla et al. (2015, Scientia Horticulturae) note that acid hydrolysis at high temperature partly or wholly destroys tryptophan, cysteine, serine and threonine, and converts many other amino acids from the L-form to the D-form, which loses its biological activity. Enzymatic hydrolysis runs below 60 °C and keeps a higher proportion of L-amino acids (Colla et al., 2017, Frontiers in Plant Science). This product comes from plant protein, broken down the enzymatic way.
Composition
| Analysis | Value | Note |
|---|---|---|
| Total amino acids | 40% (400 g/L) | Free amino acids plus short peptides |
| Free amino acids | 28.27% (282.7 g/L) | Ready for uptake without further breakdown |
| Nitrogen (N) | 5.78% | Carried in the amino acids, organic form |
| pH | 4.5–5.5 | Mildly acidic; suits foliar application |
| Source | Plant protein | Enzymatic hydrolysis; L-amino acids; no animal by-products |
Du Jardin (2015, Scientia Horticulturae) defines a plant biostimulant as any substance or microorganism applied to plants to enhance nutrition efficiency, abiotic stress tolerance and/or crop quality, regardless of its nutrient content. By that definition the amino acids are the biostimulant and the 5.78% nitrogen is a modest extra.
Mechanisms of action
01
Nitrogen metabolism switched on
Ertani et al. (2009, Journal of Plant Nutrition and Soil Science) applied protein hydrolysates to maize seedlings and measured more root and leaf growth together with higher nitrate reductase and glutamine synthetase activity, two of the enzymes that turn nitrate into amino acids. The authors read that as a stimulus to nitrate assimilation.
02
Proline and stress
Proline accumulates in many plant species under environmental stress and helps hold cellular redox balance and energy status steady (Szabados and Savouré, 2010, Trends in Plant Science). Colla et al. (2017) report maize treated with a protein hydrolysate under salt stress carrying higher potassium and proline than untreated plants, and lettuce keeping higher photosystem II activity at 25 mM NaCl.
03
Through the leaf: what is known, and what is not
Fernández and Eichert (2009, Critical Reviews in Plant Sciences) reviewed foliar uptake: stomata can significantly increase it, and humidity, temperature and light all affect how well a solute gets in, but the mechanisms are not fully understood. That is why the directions say early or late, in humid conditions, on both leaf surfaces.
04
Precursors to the plant's own hormones
Tryptophan is the starting material for the main auxin, indole-3-acetic acid, by several tryptophan-dependent routes (Mano and Nemoto, 2012, Journal of Experimental Botany). Ertani et al. (2009) found gibberellin-like and weak auxin-like activity in the hydrolysates they tested. Whether a foliar spray shifts hormone levels inside the plant is less settled, so treat this as a minor contributor at most.
05
Roots and the soil around them
Colla et al. (2017) describe a rooting trial in which tomato cuttings treated with a protein hydrolysate grew 35% more root dry weight, 24% more root length and 26% more root surface area than untreated cuttings. The same review notes that amino acids are the second most abundant compound plants release from their roots, and that over 80% of rhizosphere microbes can use them, which is why a drench feeds the soil biology as well as the plant.
06
What the field trials say
Li, Van Gerrewey and Geelen (2022, Frontiers in Plant Science) pooled 1,087 paired observations from 180 open-field studies. Biostimulants raised yield by 17.9% on average (CI 16.7–19.0%); protein hydrolysates sat in a middle group of four categories at 14.8–17.1%, and foliar applications averaged about 17%. Effects were largest on poor soils and where water was scarce. In soybean, Teixeira et al. (2018, Frontiers in Plant Science) raised field yield by at least 22% by treating the seed with single amino acids or a mix of four; sprayed on the leaves alone, only glutamate raised yield. These figures describe the literature; results on your plot will vary.
Scientific references
- Colla, G., Nardi, S., Cardarelli, M., Ertani, A., Lucini, L., Canaguier, R. and Rouphael, Y. (2015). Protein hydrolysates as biostimulants in horticulture. Scientia Horticulturae, 196, 28–38.
- Colla, G., Hoagland, L., Ruzzi, M., Cardarelli, M., Bonini, P., Canaguier, R. and Rouphael, Y. (2017). Biostimulant action of protein hydrolysates: unraveling their effects on plant physiology and microbiome. Frontiers in Plant Science, 8, 2202.
- du Jardin, P. (2015). Plant biostimulants: definition, concept, main categories and regulation. Scientia Horticulturae, 196, 3–14.
- Ertani, A., Cavani, L., Pizzeghello, D., Brandellero, E., Altissimo, A., Ciavatta, C. and Nardi, S. (2009). Biostimulant activity of two protein hydrolyzates in the growth and nitrogen metabolism of maize seedlings. Journal of Plant Nutrition and Soil Science, 172(2), 237–244.
- Szabados, L. and Savouré, A. (2010). Proline: a multifunctional amino acid. Trends in Plant Science, 15(2), 89–97.
- Fernández, V. and Eichert, T. (2009). Uptake of hydrophilic solutes through plant leaves: current state of knowledge and perspectives of foliar fertilization. Critical Reviews in Plant Sciences, 28(1–2), 36–68.
- Mano, Y. and Nemoto, K. (2012). The pathway of auxin biosynthesis in plants. Journal of Experimental Botany, 63(8), 2853–2872.
- Li, J., Van Gerrewey, T. and Geelen, D. (2022). A meta-analysis of biostimulant yield effectiveness in field trials. Frontiers in Plant Science, 13, 836702.
- Teixeira, W.F., Fagan, E.B., Soares, L.H., Soares, J.N., Reichardt, K. and Neto, D.D. (2018). Seed and foliar application of amino acids improve variables of nitrogen metabolism and productivity in soybean crop. Frontiers in Plant Science, 9, 396.
How to Use
How to use liquid amino acids: foliar spray rates and application guide
Measuring
Rates are in millilitres per litre of water: 3 ml/L is the everyday rate, so 15 ml (three 5 ml medicine spoons) makes a 5 litre sprayer. A syringe is more accurate for the smaller amounts.
Designed for foliar application
This is a foliar specialist: the liquid format, pH 4.5–5.5, and high free amino acid content suit leaf uptake. It also works as a soil drench; foliar spray is the main method. Shake well before use. Apply in morning or evening when the sun is not intense, to minimise the risk of leaf scorch and maximise stomatal uptake.
Application rates
General foliar spray: all plants, all growth stages
Shake well. Mix 3 ml per litre of water and apply as a fine foliar spray to both upper and lower leaf surfaces. Apply in the early morning or late evening when stomata are open and evaporation is minimal. This is the standard maintenance rate for routine biostimulant application throughout the growing season, from planting through harvest. Suitable for all plants: vegetables, fruit, herbs, roses, ornamentals, lawns, shrubs, and trees.
Abiotic stress foliar: post-frost, post-hail, post-herbicide, post-drought
Apply at 4 ml/L as a recovery spray immediately after a stress event: frost damage, hail damage, herbicide stress, drought recovery, or heat shock. The elevated rate delivers a larger dose of pre-formed amino acids to a plant whose own protein synthesis machinery is impaired. Can also be applied before an anticipated stress event (forecast frost or heatwave).
Quick nitrogen correction: foliar
At 10 ml/L, this rate delivers a concentrated dose of amino acid-form nitrogen that the leaf takes up directly. Use when you see nitrogen deficiency symptoms: pale green or yellowing lower leaves, reduced growth rate, stunted development. The amino acid nitrogen is taken up through the leaf as free amino acids, so it is available without first being converted from nitrate or urea. Use it to correct a deficiency, and go back to 3 ml/L once it is resolved. Not sure it is nitrogen? Why are my tomato leaves turning yellow? walks through the look-alikes.
Lawn foliar
Apply with a sprayer or watering can fitted with a rose. Use it for green-up and as a recovery spray after heavy use, drought, or scalping. Combine with Dr Forest Brix+ for a dual biostimulant foliar programme on lawns.
Soil drench: secondary method
Foliar is the main method. As a soil drench, apply at 3–5 ml/L and water into the root zone. The amino acids will be absorbed by roots and also feed rhizosphere micro-organisms. If you primarily want a soil-applied amino acid product, the Amino Acid Fertiliser powder (which also contains iron and potassium) is the better choice.
Step-by-step foliar application
- Shake the bottle well. Amino acid liquids can settle or stratify during storage. Agitate thoroughly before measuring.
- Measure and dilute. Add the measured amount (3 ml/L standard, 4 ml/L stress, 10 ml/L nitrogen correction) to water. Stir briefly. The liquid mixes instantly with no residue.
- Spray in cool conditions. Apply in early morning or late evening. Avoid midday sun: heat closes stomata (reducing absorption) and accelerates evaporation (reducing contact time). High humidity improves uptake.
- Cover both leaf surfaces. Spray upper and lower leaf surfaces as a fine mist. The underside of the leaf has a higher stomatal density and absorbs the solution more efficiently than the top surface.
- Repeat regularly. Spray every 10–14 days throughout the season at the standard rate.
Important handling notes and storage
Do not mix with strongly alkaline products. Do a jar test to confirm compatibility with other products before tank mixing. Do not pre-mix or store in diluted form; make fresh each time. Store frost-free in a cool, dark place. At temperatures below 5°C the product may crystallise. Avoid contact with eyes and skin. Keep out of reach of children. If swallowed, seek medical advice. Shelf life approximately 2 years when stored correctly in the original unopened packaging.
Works well combined with…
Tank-mix with Brix+ for a combined amino acid and growth hormone foliar programme: the amino acids provide the building blocks, the Brix+ triacontanol and cytokinins provide the signals. Add to Seaweed Powder foliar sprays for complementary trace minerals and polysaccharides. Use alongside Wood Vinegar soil drenches on alternate weeks. Feed with Dr Forest granular fertilisers as the base NPK and use this spray on top of that programme.
Questions & Answers
Frequently asked questions about liquid amino acids
It is a concentrated liquid of free amino acids, the units plants build protein from, produced by breaking plant protein down with enzymes. Sprayed on the leaf at 3 ml per litre it supplies those units ready-made, which shows up as quicker green-up and better recovery after frost, drought or heat. The 5.78% nitrogen adds a small, fast top-up.
The liquid is built for the sprayer: it is ready to dilute and most of its amino acids are already free. The Organic Amino Acid Fertiliser powder has 84.8% amino acids, 13% nitrogen, 8% potassium (K₂O) and 3,000 ppm chelated iron, and suits drenches, fertigation and seed soaks as well as foliar sprays. Liquid if you mainly spray; powder if you want the iron or plan to feed the roots.
Both, though mostly the second. At 5.78% nitrogen it makes a real nitrogen contribution at the 10 ml per litre correction rate. Its main value is the biostimulant effect of the 28.27% free amino acids, which the plant takes in intact and uses without first having to make them from nitrate. Use it with a base NPK feed for complete nutrition.
Free amino acids are single amino acid molecules not joined to others in a peptide chain, so a leaf can take them up without breaking anything down first. This product has 28.27% free amino acids out of 40% total. The remaining 11.73% is short peptides, which are broken down after application. That high free-to-total ratio is what makes it quick as a foliar.
3 ml per litre for the routine foliar spray, every 10–14 days during active growth. 4 ml per litre as a recovery spray after frost, hail, drought, heat or herbicide stress. 10 ml per litre for a quick nitrogen correction when lower leaves go pale, dropping back to 3 ml per litre once they recover. Lawns take the 3 ml per litre rate.
Yes. Foliar is the main method. As a soil drench, apply at 3–5 ml/L and water into the root zone. For mainly soil use, the Amino Acid Fertiliser powder is the better choice.
Plant-based. It comes from plant protein broken down by enzymes (enzymatic hydrolysis), with no fish or other animal source, so there are no animal by-products and it is suitable for vegan growers.
Early morning or late evening, when stomata are open, humidity is higher and the sun is not strong enough to dry the spray off or scorch the leaf. Avoid full midday sun. Overcast, dewy conditions are ideal because the droplets stay liquid on the leaf longer, giving the amino acids more time to get in.
Yes, with most fertilisers and foliar feeds, including Brix+ and Seaweed Powder. Do a jar test first with anything you have not combined before: mix a small amount at the intended dilution and check for precipitation, clumping or a colour change. Do not mix with strongly alkaline (high pH) products.
Frost-free, in a cool, dark place with the cap tightly closed. Below 5 °C it may crystallise; if so, let it come back to room temperature and shake well before use. Shelf life is approximately 2 years unopened when stored correctly. Do not store it diluted. Make up fresh spray each time.
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