A lot of our customers are curious about foliar sprays, their usage and effectiveness. Some growers swear by them, while others don’t use them at all. Whether or not you decide to use foliars in your grow room is a matter of preference. It also depends on the type of grow system that you use. Foliar sprays can deliver immediate and profound results for your plants, however tread carefully. Incorrect usage can have swift and catastrophic effects in your grow room.

One of the benefits of foliar feeding is that you can isolate and treat specific plants in your garden that are showing deficiencies or other symptoms without treating your entire crop. Foliar feeding cannot replace other types of feeding, but it’s an effective supplemental tool for growers.

Method of Action

Foliars are used to provide nutrition to plants by spraying additives directly on the leaves. Plant leaves readily and swiftly absorb nutrients, allowing sick plants to heal quickly or healthy plants to thrive. Unlike regular nutrients and additives that are absorbed by the roots, foliars are absorbed through the stomata on the leaves. Stomata are pores found on the epidermis of leaves. Generally, the stomata are responsible for the gas exchange between carbon dioxide and oxygen, but when they’re open, they can also absorb nutrients. Stomata can rapidly absorb nutrients, faster than top dressing or liquid feeding.

Application Tips

1. Most foliars can only be used during veg and the first few weeks of flower and should not be sprayed on buds or fruits. You risk contaminating the flowers you have worked so hard for. The exception to this general rule is ‘finishing sprays’ such as UBER HI-Q Foliar Spray Finisher.
2. Foliars should be used while the lights are off to prevent burning of the leaves. The liquid acts as a lens, magnifying the heat from your lights and burning your leaves. Don’t wait too long after lights out though. If growing indoors, the stomata will take about 15-20 minutes to close after the lights turn off, the plants should be sprayed within this time-frame.
3. Foliar feeding can increase the humidity in your grow room. This is something you should take into considering when deciding whether foliar feeding is for you, particularly during the flowering stage when the humidity is already higher, or if you live in a climate where you battle with humidity.
4. Always read and re-read the directions for use. Over feeding your plants using a foliar method can be extremely detrimental to plant health. To be safe, it is always better to over-dilute than under-dilute.
5. It’s helpful to think of the optimal application as a misting rather than a spraying. The goal is to achieve an even coverage of light mist on all leaves (don’t forget the undersides!). If your plants are dripping wet, you have overdone it. Less is more. We recommend a high quality pump sprayer such as Hills Garden Pressure Sprayer Bottle.
6. Always follow safety instructions, particularly when spraying for pests and pathogens. Use adequate protection such as masks, gloves, glasses, and coveralls when required.

Types of Foliar Additives

1. Nutrient deficiencies – Foliars are often formulated to address specific nutrient deficiencies. For example, if your plants are exhibiting signs of calcium and magnesium deficiency, you might consider a cal-mag foliar spray.
2. Fungicides and Insecticides – Foliars are commonly used to treat pests and diseases such as mites, powdery mildew and aphids. Example products include Crop Guard, which protect against bud rot, and Pure Crop1 which protects against mold and mildew.
3. Boosters & Stimulants – due to the rapid method of action, foliars can also be a highly effective way of delivering micro-nutrients and stimulants such as silica, amino acids, kelp and fulvic acid, to your plants.
4. Wetting agents – such as Flairform Top Wetting Agent, increase the effectiveness of foliar sprays such as foliar additives, fungicides and pesticides.