As I write this article, the summer sun is beating down directly above my head and I’m visiting my friend’s outdoor cannabis grow op. It’s noon, and the blazing heat, humidity, ultraviolet radiation and calendar clue me in that the longest day of the year has arrived.
Summer solstice (i.e., the onset of summer) in this particular garden’s location offers only a maximum of 14-and-a-half hours of daylight, and not all of that direct sunlight falls on the crops. In an indoor grow room, that length of lights-on would trigger most hybrid strains to go into flowering, without engaging in much of a grow phase.
Experienced outdoor growers tend to start their seedlings or clones in March and April to give them at least four weeks in grow phase indoors before being transplanted outside. The plants maintain grow phase until July or August, gaining height and adding girth to the main stalk — although, pre-flowering is sometimes visible during these summer months.
The heat of summer also indicates the most intense sunlight and the most stress for cannabis plants. Beginning with the summer solstice and continuing through late August — or even into September in most parts of the US — this is the time when outdoor crops need a steady supply of nutrition.
For guerrilla growers who don’t have access to clean water at their grow site, providing nutrition to cannabis can be a challenge. In this type of grow situation, a customized batch of liquid nutrition delivered via roots and foliar spraying is by far the most efficient way to feed marijuana plants.
For remote growing, a granular fertilizer product that’s quickly solubilized into the root zone can also be convenient, provided you have your outdoor grow op well scheduled.
It isn’t enough to prep the ground and transplant into fertile soil. Rather, you’ll want to send precise nutritional elements directly into roots every time it rains, or every time outdoor cannabis plants are watered by hand or irrigation. Granules should dissolve quickly and be immediately available for uptake via plants’ roots.
Using Liquid Nutrients To Feed Cannabis That’s Growing Outdoors
If you apply today’s granular fertilizers to your root zone in the months of May or June, however, they won’t be solubilized enough to feed your plants until July or August, which isn’t soon enough. For that reason, at this time of year you’ll want liquid cannabis nutrients not just for indoor growing but for outdoor growing as well.
However, you can’t apply liquid nutrients outdoors the same way you’d apply them in an indoor grow op, because the root zone is a lot larger and may be exposed to drenching rains. Plus, added cannabis nutrients tend to leach out of the root zone.
I always time my feeding of outdoor cannabis so that it occurs at the start or in the middle of a dry week, carefully watering my crop on the first day of a period when I know it won’t be raining for several days. For this, you’ll need accurate weather predictions.
If you’re lucky enough to have a period of four to seven days of no rain, you can wait until the crop is thirsty in the middle of the dry spell before feeding on day three or four. Your parched plants will immediately intake the liquid nutrition and transfer it throughout their tissues.
With a reliable water supply outdoors, use at least a half-strength pH Perfect hydroponics base nutrient at every other watering. Soil-grown plants prefer a higher pH than indoor plants grown in rockwool, coco coir, deep water culture or soilless mix.
Using your pH Perfect base at half strength while also putting supplements in with the nutrients water will assist in creating an outdoor cannabis root zone pH of 6.3–6.6.
Even better? Use Advanced Nutrients pH Up or pH Down and a pH meter to set the nutrients water into that soil target range.
In outdoor cannabis gardens growing in the peak of summer, your plants are creating tissue infrastructure and dealing with stress from heat, wind, intense sun, maybe even pests and diseases. All the essential nutrient elements present in quality fertilizers are necessary, but some more than others.
Growers who get the biggest yields tend to use a half-strength infusion of grow-phase pH Perfect Sensi Grow or Connoisseur Grow hydroponics base nutrients, delivered via the root zone.
This root-zone feed should also include potassium silicate in the form of Rhino Skin, B vitamins in the form of B-52, nutrients and beneficial compost tea compounds from Mother Earth Super Tea Organic, carbohydrates from Bud Candy, and humates and fulvates from organic Ancient Earth. These supplements should be delivered at full strength.
Alternative Nutrition For Remote Outdoor Cannabis Grow Sites
Peak summer is the time when your outdoor cannabis crop is building the height, side branches, leaves, stalks, and intracellular processes necessary to create structure large and sturdy enough to support buds the size of baseball bats.
Providing customized nutrition to your outdoor cannabis crop in the full heat of summer requires a lot of water, which is why I recommend a half-strength dose of the hydroponics base nutrients, so you don’t burn the roots with an overdose of nutrients.
Alternate the feeding of base nutrients, Rhino Skin, B-52, Ancient Earth and Bud Candy with a one-quarter strength solution containing fish emulsion and kelp. These two ingredients provide a nitrogen-rich feed program, especially because kelp is a plant tonic that stimulates photosynthesis, nitrogen uptake, root development, height and stalk strength gains, and the growth of beneficial root-zone microbes.
Use the fish emulsion and kelp formula in the following situations:
- If you’re growing outdoor cannabis in a location that receives more than four inches of rainfall per week.
- If you’re growing remotely and you can’t easily access your crop.
- If you don’t have access to enough on-site or carried-in water to do customized liquid nutrients feeding.
Distribute a few ounces of the fish emulsion and kelp formula in a circular pattern around the base of each plant, at least nine inches from the main stalk.
Create a peak summer pH 5.7 foliar spray at 245 parts per million that combines in equal amounts Sensi Grow, B-52, Sensi Cal-Mag and Rhino Skin. And do your foliar spraying early in the morning or at twilight to prevent direct sun from evaporating the water and baking the nutrients onto the leaves so they can’t be absorbed.