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molasses growing cannabis

Incorporating molasses into your regular feeding cycle is most effective and easiest when it’s combined with other ingredients in well-balanced liquid fertilizers. All of the nutrients in the solution are more readily absorbed when molasses is in the mix and the sugars are available exactly when plants need them most.

We all know that sugar isn’t the healthiest food for people, but for plants and the microorganisms that support them it is a valuable source of energy and nutrients, boosting both the quantity and quality of your harvest. We’re not talking about ordinary table sugar here, but molasses, a by-product of sugar production. Before you grab a bottle of molasses from the shelf at your supermarket and pour it on your crop, here’s what you need to know about where it comes from, how it works, and how to use it.

When sugar cane or sugar beets are processed, the pure sucrose is extracted, leaving behind highly viscous syrup. After that fluid is boiled, it becomes what’s called “Barbados” or “mild” molasses. Very sweet and light in color, it’s used to flavor hot cereal, tea, and other foods. A second boil yields dark molasses, an amber-colored syrup that’s commonly used in cooking and baking. When boiled a third time, much of the sugar is gone and what’s left is dark, strong-flavored – almost bitter-tasting – blackstrap molasses. It is used primarily in cattle feed and it’s also a key ingredient in dark rum.

How Molasses Helps Your Plants Grow

When your plants are two to three weeks from the end of their growing cycle, stop giving them molasses and other fertilizers and give them only water to “flush” out any unused nutrients. If you have leftover blackstrap molasses, you can mix it up at a rate of about a cup per gallon and pour it on your compost pile, where it will stimulate the good microbes at work there, too.

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The key minerals that make molasses a healthy food for people are vital for plants, too. Potassium and calcium, in particular, play an essential role in the processes that plants go through as they form buds and flowers. Even better, the sugar works as a natural “chelating” agent, binding it to other nutrients so they are more readily absorbed by plants.

Molasses: What is it?

The repeated boiling concentrates nutrients, making blackstrap molasses a rich source of calcium, magnesium, potassium and iron. Because of the high mineral content, health-conscious eaters use blackstrap molasses as a supplement in their diets.

If you want to try a more DIY approach, you can buy blackstrap molasses – just be sure to get the unsulfured type so it doesn’t kill off the very microbes you want to feed. Add it to your nutrient solution at a rate of about 1/4 cup per gallon. While you may hear recommendations about spraying molasses solution on plants directly, the residue can attract fungus gnats and other pests to your grow room. Also, the sticky substance is prone to clogging sprayers.

Molasses growing cannabis

Put all these distinctions together, and you find that the most suitable form of molasses for growing cannabis is organic unsulphured blackstrap molasses.

Molasses comes in several types, varying in extraction method and sweetness. Molasses extracted from sugar cane is typically made into a food flavoring or sweetener, while molasses extracted from sugar beets has a bad taste and smell and is, therefore, used primarily as an additive in animal feed.

Most molasses naturally contains some amount of sulphur, but molasses from sugar cane may also contain added sulphur dioxide as a preservative and anti-microbial agent to keep fresh the raw sugar cane prior to processing.

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A good starting dose of molasses for cannabis plants in their vegetative, or pre-flowering, stage is 4 to 5 ml per liter of water. Once the plants start flowering, you can then increase the dose slightly.

Will molasses make my marijuana buds bigger? Will it make them taste sweeter?

The amount of molasses to use depends on several factors, including:

Then, once the sugar crystals are extracted to make sugar, the syrup remaining is molasses.

Be aware, as well, of the effect of molasses on the pH of your water, feeding regimen and soil. Always regulate the pH of anything touching your cannabis plants to make sure they’re pH neutral, or approximately 6.8-7.2.

Why is molasses so beneficial to cannabis plants?

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Molasses contains most of the same nutrients found naturally in healthy soil, making it an appropriate supplement or additive to keep cannabis plants consistently well-fed.