Foliar feeding is a a great way to supplement your feeding. Whether to correct a nutrient imbalance, get the plants eating through nutrient lockout at the roots, or just to get a little more food in there to boost your buds, feeding cannabis through the leaves is fast and effective.

BE CAREFUL: Start with lower than recommended dosages, it is really easy to burn your plants.

Conventional wisdom tells us that plants can absorb moisture through the stomata on the underside of the leaves, so small doses of nutrients can be diluted in water and sprayed on the underside of the leaf, where the plant (or weed) can absorb and use them directly where they are needed.

Now, since we are playing with more interesting things than conventional wisdom, I recommend a product called Penetrator by Dutchmaster.

Traditionally the only holes in the waxy cuticle are the stomata on the underside of the leaf, however what Penetrator does is create a series of tubes coming in through the cuticle into the mesophyll layer. These tubes are lined with water, and evaporate away when the feeding is over It also contains a chemical agent that helps maintain the stability of the reaction. With traditional foliar feeding, the leaf can only uptake nutrients until it runs out of electrical charge, then it begins to close up and reject whatever is left. With Penetrator leaves are able to uptake more nutrients through both sides of the leaf, and they receive more nutrients at each site.

Since foliar feeding is topical, it allows the plant access to the nutrients it needs, at the location it needs them. It allows the plant to recover from any kind of deficiency quickly with minimal energy loss.

Foliar sprays should be alternated, to help the plant thoroughly ingest every feeding. I recommend foliar feeding 2-3 times a week during weeks 2-6 of flowering. I use concentrations of about 400-700ppm of about half nutrient/half Penetrator. Start at the low end, or even a little lower. Always use pH neutral water, whatever the pH of your medium is, 5.6-6.0 for hydro, and 6.0-6.3 soil. Since Penetrator allows your plant to absorb more food, use lower than recommended doses until your plants adjust to foliar feeding.

Products I use to foliar feed:

B-52 – B-vitamins and Norwegian Sea Kelp extract make this a great source of trace minerals. Also B-52 helps you plants be more tolerant to heat and drought. There are two essential plant hormones, auxins and cytokinins. Auxins encourage apical dominance, telling your plant to shoot straight up from the tallest point. Cytokinins do just the opposite, they signal the plant to stop elongating, and to start bushing, and noding closer together. Norwegian Sea Kelp is rich in cytokinins, so wait until you are satisfied with your plant’s height before you spray this one. Start around 200ppm B-52 200ppm Penetrator, and work your way up.

Revive – Advanced Nutrients gift to frustrated cannabis growers everywhere. It is a special blend of super chelated micro-nutrients. If for any reason your plants start to yellow, add 200ppm of Revive to the reservoir, and mix up 100ppm Revive 200ppm Penetrator in a foliar spray. You will see your plants returning to green in less than an hour. This stuff is amazing, and it works before your eyes. (In a pinch, substitute Ca-Mg+, same idea just not as immediately effective)

Humic/Fulvic acid – These are the decomposing remains of peat bogs, refined from leonardite (WARNING: exposure to bare skin may cause skin and eye irritation, handle with gloves). They contain loosely bonded elemental remains that your plant uses to break down its food. Humic acid helps with the breaking down of trace elements, where as Fulvic helps with the breakdown of sugar. Foliar feeding of these basically chemically induces hunger. These natural acids create a demand for nutrients wherever applied, so when applied in small doses directly to the flower, it tells the plant to send more food to the buds. Foliar application also helps your plants get through nutrient lockout at the roots. These two can be combined when added, but start off light, its way easy to burn your buds.

Note: I discontinued foliar feeding at the beginning of week 7, and began spraying pH 6 water on the leaves to help them intake the rest of their food. About 3 days later I found the beginning signs of powdery mildew. It is too late to spray fungicide, so I have to attack the mildew itself. I turned the air conditioner up to impede growth, and dry out the air. Anywhere that is already infected with powdery mildew (in the shade, near the bottom) it can be cured with a foliar spray of 1pt whole milk to 9pts water. The lactic acid will eat the powder mildew alive.

Foliar feeding is feeding your plants through their leaves. I think the best way to explain it is by first explaining the leaf itself. Warning, for those interested in growing weed, and not so much the science of it, here is the article on foliar feeding. Here’s a diagram:

• The Cuticle is the waxy protective layer on the top side of the leaf, it helps the plant retain water.
• Next comes the Upper Epidermis (botany: Adaxial Epidermis) this is made up of clear epidermal cells only a single cell layer thick. These cells are jammed side by side to offer protection from the outside world. Epidermal cells contain one of the precursors (cutin) for the cuticle. The Epidermal cells are also responsible for my personal part of the plant, the epidermal hairs aka trichomes.
• Under the Epidermis lie the Palisade Mesophyll cells. These are large cylindrical green cells. These contain the chloroplasts, they absorb sunlight, and turn it into sugar.
• The Spongy Mesophyll is a bunch of funny shaped loosely packed cells used for gas exchange.
• The Veins are contained within the mesophyll layer. The Bundle Sheath cells create passageways throughout the plant. Xylem is water containing nutrients brought up from the roots to the leaves. Phloem is the sap containing all the sugars made by photosynthesis which the leaf sends back to
• The Lower Epidermis (botany: Abaxial Epidermis) contains 2 different types of cells, stomata and guard cells:
• Stoma (plural: stomata) is a pore between a pair of guard cells that allow plants to breathe. Leaves need CO2 (carbon dioxide) for photosynthesis, and create O2 (oxygen) as a byproduct. Since the inside of a plant is mostly composed of water, in order to ‘inhale’ CO2, it has to displace (‘exhale’) water vapor from within the leaf, this is called transpiration.
• Guard Cells are bean shaped cells that control the stomata. They contain chloroplasts, so they manufacture sugars, their job is to sense how much water is being released by the plant, and close the stomata to stop transpiration. This is a really complicated process, for more information here’s Wikipedia, scroll down to ‘opening and closure’.
• On the bottom is a another, thinner, cuticle layer.

So, now that we THOROUGHLY understand the leaf, lets explore methods of feeding our plant through the leaves.

Foliar feeding is a a great way to supplement your feeding. Whether to correct a nutrient imbalance, get the plants eating through nutrient lockout at the roots, or just to get a little more food into a healthy plant, feeding through the leaves is fast and effective.

BE CAREFUL: Start with lower than recommended dosages, it is really easy to burn your plants.

As I explained earlier, these were our veg nutrients… because this is what the guy at the hydro store recommended. I have always used Foxfarm’s Grow Big For Soil, which also comes in a hydro version (which has a lower N-P-K, and they add calcium and magnesium), and I have always had great success. However since this is our first hydro run, we took the guy’s word for it. I was fairly unimpressed with these. The plants grew, but didn’t skyrocket. Also with the prescribed low dose of cal-mag I ended up with deficiencies. I think next round it’ll either be Grow Big or Advanced Nutrients SensiGrow A-B.

Which brings us into flowering, and our new food AN’s SensiBloom 2 part blooming nutrient.  These nutrients are designed for hydro, the label has accurate conversions from tsp.-ppm. I guess I don’t really have an opinion on this one yet, it comes highly recommended from some friends, I guess we’ll see

Big Bud comes in week two as the MOAB phases out and continues through week five. It is packed full of amino acids. I think AN puts it best “What the heck are amino acids? Oh, they’re just the building blocks of proteins and other important factors that are absolutely essential for plant life, growth and yield, that’s all!”

Cha Ching is Foxfarm’s finisher. You run it the last couple of weeks (6-8  with indica, later with sativas) and helps with resin and oil production, as well as adding weight and density. I have seen this work wonders on soil plants, and I’m really excited to use it again.

Liquid Carbo Load is basically really expensive liquid sugar. Your plant loves sugar, it makes sugar, sugar increases yield, bud density, and that sweet deliciousness we all love. I hear molasses is just as good, but only the best for my little girls!

Diamond Nectar contains trace amounts of Fulvic Acid. This one is important. It helps the plants break down their sugars, you can’t add enough of this stuff.  I recommend the high dose, 2tsp per gal. During the second half of flowering, supplement feeding with foliar spray 1-2x a week. Use double the recommended dosage for the foliar spray. Outside of California you can replace this with fulvic acid, AN makes Grandma Enggy’s F1 (Fulvic Acid) but unfortunately they won’t ship it out here.

It lasted like 2 weeks.

I suggest the gallon size.

B52 is a life saver. It is a blend of B-vitamins, Humic Acid, and Norwegian Sea Kelp (Ascophyllum Nodosum). The combination of the three helps your plant cope with environmental stresses like drought, and heat. The sea kelp contains hormones called cytokinins that tell your plant to stop vertical growth, and reduce the distance between nodes, so don’t start using this until a couple weeks into flower, when your satisfied with your plant’s height. I found agricultural studies that found Ascophyllum Nodosum when applied in a foliar spray increases yield size and density.