LED Grow Light

7 Reasons Why Cannabis Plants Grow Slow-Part III

We’ve introduced 6 of the 7 common reasons why cannabis plants grow slow in the previous blogs. Last but not least: Sometimes plants want to be left alone. We’re going to share ways to make cannabis grow faster too.

7.) Sometimes Plants Want to Be Left Alone

Unfortunately, you can “over-love” your plants. Overwatering is so common among new growers because they are trying to give something good to their plants and get a little carried away.

Sometimes plants need to be left alone. There may be days or even weeks where they really don’t need anything from you besides water.

If you’re wondering why plants are growing slowly, yet you’re constantly messing with plants, touching them, bending them, defoliating, etc., you may need to give them a break until they start growing fast again. Fast-growing vegetative cannabis plants can handle almost anything, but when a plant is growing slow you should focus on providing a good environment, just the right amount of nutrients/water, and staying hands-off until it’s recovered.

How to Make Cannabis Plants Grow Faster

Now that you know what may be causing the problem, get the solution. Follow these principles and your plants will be growing inches a day!

1.) Watering

Proper size pots – Much easier to avoid over or under-watering if plants are in an appropriately sized pot. Seedlings grow fastest in small pots where they’re less likely to get waterlogged, while older plants want bigger pots to spread out their roots. 

Good drainage – Soil or coco should not seem muddy, dense, or thick. Water should be able to drain freely from the bottom of the pot (if there aren’t any drainage holes, you need to add some yourself). Learn about growing in soil or coco. 

Aim for watering every 2-3 days – Giving just enough water at a time so you can water every 1-3 days produces the fastest growth. Watering every day produces excellent growth but you have to be careful not to give too much at a time. It takes a delicate dance to avoid overwatering when watering that often. We recommend aiming for every 2-3 days for beginners since there’s less room for error.

Plant pots should be feeling a little light and the top soil should be dry or mostly dry by the time you give water again. If you’re giving so much water at a time that it takes 4+ days for your grow medium to dry out, you likely will achieve faster growth by giving less water at a time. However, some growers prefer a hands-off approach to growing and may not mind plants growing a bit slower if it means they get to water less often. If you need to water more than once a day, the plant is begging for a bigger pot! 

Nutrients and PH – Make sure your plants are getting the necessary nutrients. As far as pH, some growers get lucky and happen to have perfect water for cannabis plants. However, if your plants are struggling and you don’t know why, the pH being high or low is one of the most common reasons. If your plants are struggling and you haven’t checked the pH at all, get a PH Test Kit and do that first. It’s super simple to adjust the pH (just add “PH Up” or “PH Down” to your water), you just need to know how much to add, and you can’t find that out without testing!

2.) Environment

Humidity – Keep humidity around 50% RH for the fastest possible growth. Plants can grow at higher or lower humidity levels, but some plants struggle because humidity affects how well water moves through the plant. Since each leaf is constantly giving off water vapor, it’s more common for growers to struggle with high humidity than low humidity, but it still goes both ways.

  • Dry air under 35% RH can limit plant growth, and under 25% RH may even cause deficiencies and other odd symptoms
  • High humidity above 70% often makes plants droopy and slows down growth. In the flowering stage, high humidity can cause buds to grow more fluffy.

If your air is dry, you may consider turning down any fans to help keep humidity pockets near your plants, though that can only do so much. If the air is really dry, you may need to add a humidifier (raises temperature and humidity) or swamp cooler/evaporative cooler (lowers temperature, raises humidity).

If you’re struggling with high humidity, you may need to add an exhaust fan to vent out humid air and bring in fresh air. If your plants are in a grow tent, typically an exhaust fan that’s set up properly can keep the humidity just a little higher than in the room. If the humidity is much higher in the grow space than the surrounding room, that means you need to help equalize the air with an exhaust/intake fan, or by blowing the air around. If the humidity of your actual room is high, no amount of fans can fix that. In that case, you’ll need either a dehumidifier (raises temperature, lowers humidity) or an AC (lowers temperature and humidity) to bring the RH into a better range. 

Temperature – Cannabis seedlings and young plants love when it’s warm but not hot. Plants typically grow the fastest if the temperature stays around 73F at night and 79F during lights-on. Under LEDs, keep it just a bit warmer, 74F at night and 80F during lights-on. Plants can definitely grow well when it’s a bit warmer or cooler, but you tend to get the fastest growth in that temperature range.

To be continued…

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