How to take your crop quality and yield to the next level
by Omar Sacirbey
For cannabis cultivators seeking to distinguish their product in an increasingly saturated market, advanced nutrients can make the difference.
“It’s not hard to produce B+, A cannabis, but the nutrients can take you into the A+ range,” said Daniel Sloat, owner-grower at AlpinStash, a craft cultivator in Boulder, Colorado.
But there are right and wrong ways to use nutrients such as nitrogen, potassium and zinc. Doing it correctly requires careful observation of your plants, experimentation and moderation – given that it’s possible to overdo nutrients. If a grower can bring that approach to nutrient use, both the quality of their cannabis and the size of their yields will improve.
It’s important to keep expectations in check and avoid slacking off on other factors that can affect crop quality, however. While nutrients can improve product quality and yields, they aren’t as important to the plant’s health as factors such as light and temperature.
“It doesn’t matter what nutrients you use if your environment is poorly managed,” said Sloat, whose cannabis is sold in about 10 recreational retailers and dispensaries in Colorado.
Dial lt In
Cannabis thrives on three so-called macronutrients: nitrogen, potassium and phosphate. A slew of micronutrients – including zinc, copper, amino acids and algae, among others – also can be used. But these two groups don’t go in at the same time or in equal parts.
“It’s generally accepted that you want lots of nitrogen early to help with that vegetative growth, to help the plant establish itself, establish a big canopy,” said Daniel Hopper, chief cultivator for Silver State Relief in Sparks, Nevada, a dispensary with a vertically integrated grow site. “And then when you transition into flower, you want the plant to stop putting so much energy into the vegetative growth and to focus on flower production.”
Grapes are the same way, added Hopper, who has a Ph.D. in plant biology and worked in wine grape cultivation before marijuana.
“The idea is that you drought stress the plants so they produce more grapes or buds. And if a plant puts more energy into its fruit, it makes a higher-quality fruit,” he said. “As you transition into flower, you add more potassium and phosphate, and that should stimulate the plant to put more energy into flower production.”
Many nutrient mixes also contain micronutrients. But Sloat prefers the Nectar for the Gods line because it’s natural and the micronutrients come in individual bottles.
“You have greater control over what your plants are getting,” Sloat said.
How can you tell if you’re overdoing it or underdoing it with nutrients?
“The way you know how much is too much or too little is by looking at the plant, really knowing the plant that we’re growing. You can see it needs more of this, it needs less of this,” Sloat said. “A lot of it just comes down to looking at your plants and seeing what they need.”
Pick a Bone
Sloat likes nutrients that are calcium-based.
Nutrients bond well with calcium, and plants also like absorbing calcium. The result: Plants will absorb the nutrients bonded with the calcium.
Sloat’s preferred product line also sources its bone meal from a local, grass-fed slaughterhouse, “so it’s all very high-quality nutrients,” he said.
Know What’s Inside
Flower enhancers, which are supposed to increase the size of your flowers, sound good. But they might do in your crop.
Many flower enhancers don’t list the chemicals they contain. Some of those chemicals might be hazardous or even result in your crop failing a lab test.
For example, many nutrient mixes contain plant-growth regulators, also known as plant hormones. Nevada tests for them, and their presence can sink your crop.
“That was always a concern, what’s actually in these nutrient lines,” said Hopper, who uses the House & Garden nutrient line but is also developing his own.
If still in doubt, take the nutrient mix to the lab that tests your marijuana so the staff there can tell you what it has and doesn’t have.
Do lt Yourself
Nutrient mixes can be expensive, and some cultivators believe they can deliver the same or better bang for less money by developing their own.
Hopper, for instance, teamed up with a local agronomist to develop an in-house mix, with the nitrogen and potassium-phosphate portions mixed with the micronutrients that he prefers at the levels he favors.
Hopper really likes using algae extracts, which some say boost plant growth and resistance to pests. But they can be expensive. However, Hopper located a Norwegian provider of sea kelp whose price is a fraction of what he previously paid for algae extracts.
Developing nutrients “is going to save us quite a bit of money,” Hopper said, putting the savings at about $60,000 to $70,000 annually.
Give the Nutrients a Rest
To avoid overdoing it with nutrients, Sloat puts his plants on a three-day cycle.
The first two days are allocated to feeding and the third is reserved for either water or a water-compost mix.
When Sloat runs just water or water and compost, “the microbes in the soil can continue to break down the nutrients and get it to the plants as they need it, as opposed to forcing it into them.”
“You can overfertilize the plant and have a reduced yield,” Sloat said. “Like people, plants operate best when they’re slightly hungry.”