Watering
Seems like an easy thing, water when the plants need it, yet watering is one of the biggest challenges to new growers.
Only water when the soil is dry. Never water moist soil. A couple ways to determine if your soil is dry, pick up the pot, if it’s heavy, it’s full of water, if it’s really light, it’s dry. Water is heavy, 8.34 pounds a gallon. Get a feel for how light the pot is before you water the first time, this is how light it should be when you water it. Pick up your pot after you’ve watered and feel how heavy it is.
Marijuana plants like wet/dry cycles, also referred to as the flood/drought watering method. Water fully til there is a little runoff then let it dry out and repeat as needed.
In some cases you may not to able to use this method, if you have a small plant in a big pot for example, like say a sprout in a 5 gal pot, flooding the pot is not going to work as it will take weeks to dry and your sprout will be suffering from over-watering and may even damp off or get root rot and die due to staying wet for too long.
In that case you should give small enough amounts of water that will dry up within a few days. This is why I don’t do small plants in big pots, start in a small pot where you can flood/drought without issue and move up to bigger pots as your plants get bigger. this is the way for fast plant growth. Will cover transplanting in more detail in a latter post.
Over watering
One of the biggest problems I see with new growers is over watering. Over watering occurs when plants are watered too often (or too much in a small plant/big pot situation). In a proper size container for the plant, you can’t really over water by giving too much water at once. When using a good potting soil like Happy Frog and pots with proper drainage, the soil is only going to hold on to so much water and the excess will drain off (don’t let your pots sit in that excess water as it will eventually absorb too much water, empty your trays after watering).
My large plants in 7 gal fabric pots will only hold on to about a gallon of water, the rest will drain off. I could give it 2 gallons of water and 1 gal will drain off, I could give them 10 gals of water and 9 gals are going to drain off. As long as the drained off water is removed, it doesn’t matter how much water I give them at once, it will not cause an over water problem. This is why flushes don’t create an over watering problem. What will cause an over watering problem is if I water them again before the soil has dried out. Watering too soon/too often causes over watering.
My plants are droopy
The #1 sign that you are over watering is droopy plants. A tiny bit of droop at lights on and lights off times can be normal but if droop persists for an hour or more before or after lights on/off or if droopy all the time - most likely your plants have been over watered. How do you fix it? Stop watering and let your soil dry up before watering again. If your plants are droopy and you usually water every 3 days, push that to 5 days and let them dry up more before watering, just watch them, droop is not as bad as they look when they hit the “really need water now or I’m going to die” look, which is completely limp leaves, looks way worse than the droop.
Don’t buy the “They look droopy cause the lights just came on”. Over watered plants will typically look the most droopy at lights on and lights off times, they may perk up some during the middle of the light cycle but will droop a good while after lights come on and before lights go off.
My light just turned on in my flowering tent, those of you familiar with HPS lights would know the light just came on because it hasn’t gone yellow yet, takes a minute or 2 for that to happen, let’s take a look
No droop here at lights on since they are not over watered.
My over watering story
Yes, even an experienced grower like me can over water. I recently over watered the plants in the flowering tent, same ones above in the picture, they did recover quickly. After moving my girls from the veg tent to the flowering tent and setting them up on the screen. I continued the watering at every 3 days and they were fine for a week (a couple waterings). But then I noticed a little droop, the droop lasted a couple hours after lights came on, then they perked up for most of the 12 hour light cycle and then started drooping an hour or 2 before lights out. I recognized it as over watering but my mind kept trying to think of other reasons they might be drooping, just pruned a lot, change of light spectrum (from MH to HPS), etc… I tried to convince myself that it was not over watering. The plants being SCROGed now, you can’t pick up the pots, and even digging my finger down a few inches wasn’t telling the whole story in the big 7 gallon fabric pot. But after arguing with myself breifly, I accepted that they were being over watered. The change of light schedule from 18/6 to 12/12 (and less vegetation from the pruning, trimming, and defoliation) was enough change that the plants were no longer drinking up all the water in 3 days as they did in veg. So when day 3 came, no water, just watched the plants to make sure they didn’t go limp (dying from thirst mode), then day 4, no water, just watched them, didn’t go limp, hell they started losing the droop already, day 5 droop mostly gone and soil was dry, watered the plants fully, droop did not return. Over watering problem solved.