New growers will no doubt scratch their heads and reach for the pipe when asked about pH. The pH of something, usually a liquid, refers to the acidity or alkalinity of said liquid. The pH scale starts at 0 (very acidic) and goes up to 14 (very alkaline). A value of 7 is a neutral pH level. Marijuana likes a slightly acidic pH, so shoot for a pH of 5 or 6 in your nutrient solution. Cannabis plants cannot absorb nutrients properly if the pH at their roots is too high or too low. So even if the nutrients are present, you’ll still get what look like nutrient deficiencies if you don’t maintain the right pH.
While a purely hydroponic system would be cool to have, most newer growers stick to peat and perlite to raise their crop. It’s a low cost, low tech system, but your plants will love it. It only takes a week or so to find the right feeding and watering amounts in order to get the best yield possible.
Most peat and perlite pots need to be fed and watered every two or three days. The general rule is to feed in the morning when the grow lamp turns on and water just before the grow lamp turns off. If, after a few days, the growing medium isn’t dry an inch down you’ll have to cut back on the amount of nutrient solution and water you’re using. Know an over watered/fed plant by stunted growth and dead older leaves. Don’t confuse this symptom with nitrogen deficiency.
On the other hand, if your growing medium dries out before a full day has past you’ll have to feed and water more often not more at once. You might also want to ponder using a humidifier in the growing area. Sometimes a dry environment can cause symptoms like nutrient deficiencies. Wilting is the first symptom of an under fed/watered plant.
Once you’ve perfected your pH and developed a good feeding and watering plan, you’ll have to give a few moments thought about the nutrient solution you use. During the green leafy stage of life for cannabis you might not pick up on a nutrient deficiency since the plant has all of the trace elements such as zinc, boron, iron, sulphur, phosphorous and potassium to grow healthily in its infancy. These trace elements are present in the seed, which lasts for the first two or three weeks of growth.