Managing pH with Grow Nutrients for Coco
When your cannabis plants are in the growth stage, they need a pH level between 5.5 and 5.8. During the floweringÂ stage, a higher pH between 6.0 and 6.3 is preferred. Test the pH of any water and nutrients that you plan to feed to your plants.
Coco coir’s natural pH is between 5.2 and 6.8, which makes it ideal for growing cannabis. If you’re using coco coir along with another medium such as soil, you should keep in mind that this will impact your pH and require regular testing. Some nutrient solutions are uniquely balanced to help you maintain proper pH levels in coco coir. However, you can only rely on these in the absence of regular testing when you’re using pure coco coir without other amendments.
It’s best to continue testing the pH routinely with any chosen nutrient supplement for at least one growth cycle to determine its effectiveness at maintaining the proper pH. Over time, you may develop a feeding schedule that allows you to scale back on your pH testing.
Calcium, Magnesium, and the Cation Exchange in Coco Coir
Calcium and magnesium deficiencies are common for plants grown in coco coir. This is the result of the unique cation exchange sites in this growing medium. Each medium handles cation exchange differently. Coco coir’s cation exchange sites are packed with potassium and calcium at first. However, these bonds are weak and easily broken. This means that the coir will release the sodium and potassium readily as other nutrients become available.
Coir forms particularly strong bonds with calcium and magnesium. Once a cation exchange site has bonded to calcium or magnesium, it will stay relatively stable. The absorption of calcium and magnesium is therefore more pronounced with new coco coir. However, you should continue to provide an abundance of these nutrients to your plants because new cation exchange sites can become exposed as the coco breaks down.
Give your plants a healthy boost of calcium and magnesium with a product like Cal-Mag from Botanicare or CaliMagic from General Hydroponics. You should feed your plants with a full-strength calcium and magnesium solution until they’re in the last half of the flowering stage. You’ll notice that the plants stop growing new leaves and stems at this point.
Keep in mind that you’re not really feeding your plants with this supplement as much as you’re feeding the coir. The coir needs the greatest amount of calcium and magnesium when it’s fresh. However, in the early growth stages, your plants will rapidly expand their root systems, which breaks down the coco coir further. This exposes new cation exchange sites and creates an ongoing need for these nutrients. Continue with the calcium and magnesium until growth slows in the second half of the flowering stage.
Scheduling the Best Nutrients for Coco
When feeding plants in coco coir, it’s important to think about your watering schedule. If your plants are in coco alone, their only source of nutrients is the water you provide. If you’re watering your plants daily, you can typically use a solution that’s only half-strength based on the product’s recommendations. If you water less frequently, a full-strength solution is necessary.
Adjust your feeding schedule to correspond with your plants’ growth stages. As mentioned previously, calcium and magnesium are more important in the early stages. In the mid-to-late flowering stage, your plants need more phosphorous and potassium. Your coco coir will likely release some potassium on its own, but you shouldn’t rely on the coir exclusively. Continue to feed both of these nutrients to your plants.
Finding the Best Nutrient Line for Coco
Several nutrient solutions are uniquely designed for cannabis plants grown in coco coir. These are the best options because the legwork of calculating and balancing the best nutes for coco is already done for you. Some of the top contenders for the best nutrient line for coco include:
- pH Perfect Sensi Grow from Advanced Nutrients: This two-part soil amendment is formulated just for coco coir to provide ample calcium and magnesium while scaling back slightly on potassium to prevent potassium toxicity. An organic surfactant is included in the mix to make it easier for plants to draw up nutrients from the water.
- Big Bud Coco from Advanced Nutrients: Big Bud is a powerful liquid fertilizer for the flowering stage that delivers on its promise to create bigger plants no matter what you’re using it on. This product is designed for coco coir media in systems with continuously flowing water, such as drip irrigation, deep water culture, hydroponics, or aeroponics.
- COGr Vega from Canna: This two-part formula focuses on the needs of plants in the growth phase. Formulated for a coco coir medium, this product makes nutrients readily available to aid in fast cultivation.
Diagnosing Nutrient Deficiencies
Keep a close eye on your plants to make sure that you’re always providing the best nutrients for a coco grow setup. While a feeding schedule can help, you should always rely on your plants’ health as the final determination of what you need to feed them. Watch out for these particular issues:
- Calcium deficiency: Root tips will wither as the lower leaves curl and develop brown edges and yellowish-brown spots.
- Magnesium deficiency: The area between the veins of older leaves will yellow, and the leaves will develop rust-colored spots. These signs don’t show up until the deficiency has persisted for three to six weeks.
- Nitrogen deficiency: Though not specific to coco coir growth, this is the most common problem for cannabis overall. Nitrogen deficiency causes leaves to lighten and yellow.
With the proper nutrient products, you can make sure that your plants are well-fed in their coco coir medium so that you get the results you’re after.