Foliar Sprays

Why growers feed through the leaf

Leaves absorb. Growth Technology's own copy for GT Foliar credits Dr H.B. Tukey's 1950s radioisotope work for settling it: nutrients enter through the stomata and transcuticular pores of the leaf, then move around the plant to wherever they are needed. That gives foliar feeding one clear advantage over root feeding — speed.

It gets used for two reasons. The first is rescue: root damage from over-watering, a pH that has drifted, or temperatures at either extreme all stop roots doing their job, and a foliar feed keeps the plant fed while you fix the root zone. The second is simply a boost — Accent's Green-Up targets yellowing in cuttings and clones and the nitrogen or magnesium shortfalls young plants hit before their roots can keep up.

Our range of foliar sprays

Foliar feeds and leaf tonics

GT Foliar is the most complete formula here: a full mineral profile with chelated trace elements, 20 amino acids, three types of kelp, fulvic acid, silicon and a wetting agent, ready to use in a trigger pack and applied two to three times a week. Bloom's Groigen and Florigen split the job by stage — Groigen through grow, Florigen through flowering — both at 20mL per litre. Optic Foliar Overgrow and Rev carry NPK, micronutrients, vitamins and amino acids, and SNT's whole-leaf aloe powder is a 200:1 concentrate.

Clone and seedling mists

Young plants have the least root mass and the most to gain. FloraMax Clone Spray is built for foliar uptake at 25mL per litre, and is candid about why that matters: its own label notes that ordinary root-enhancer additives are designed for root uptake and are not ideal sprayed on a leaf.

Spreaders and spraying under lights

Optic Foliar Transport is not a feed. It is a spreader and wetting agent, added at 7.5mL per litre to any foliar solution so you can spray under lights without burning and without reaching the leaf undersides. Optic Foliar also says not to pH-adjust a foliar spray.

Specialty sprays and sprayers

Optic Foliar Switch is used in the first two weeks of flower, BudWise is a plant feminiser applied in the dark cycle before flowering, and O16 is a stabilised oxygen solution usable as a foliar or a root application. To apply them, the Hydro Axis 8L pressure sprayer runs at 0.25–0.28 MPa with an adjustable mist-to-stream nozzle; the Silvan 1.5L is a smaller nitrile-sealed unit rated to 2 bar.

How to get a foliar spray right

1. Spray in low light, or with the lights off. Bloom's Groigen and Florigen both instruct spraying with the lights off to avoid burning, and GT Foliar asks for low light and a fine mist over leaf tops and undersides. Optic Foliar Transport is the exception, built for spraying under lights.
2. Mist, do not drench. GT Foliar warns that soaking the plant compromises its ability to absorb. You want an even film, not run-off.
3. Keep it off the flowers. GT Foliar advises against spraying blooms and buds because it can lead to bud rot — the main reason foliar programs taper off through flowering.
4. Watch the temperature. In excessive heat the stomata are generally closed, so spraying then is wasted product. Early morning or evening gives the leaf longer to absorb.
5. Do not pH-adjust the spray. Foliar solutions are not reservoir solutions. Optic Foliar states this directly, and mixing habits from your tank do not transfer.

Foliar sprays or pest control?

The two overlap because they share a delivery method, so the useful question is what a product is for, not how it goes on. A miticide sprayed on a leaf is pest control; a kelp and amino tonic sprayed on a leaf is a foliar feed. Products that genuinely do both — Athena's IPW leaf wash is the clearest example — sit on both pages. Treating something, start at plant pest control; feeding something, you are in the right place.

If the symptom that brought you here is discoloured leaves, the store's guide to yellow leaves and common grow problems is worth reading before you spray anything, and the root stimulator range covers fixing the root system that caused it.