After flowering begins, the marijuana plants need less nitrogen and more phosphorous and potassium, so it’s time to switch your fertilizer. If you are using a water-soluble chemical fertilizer, you should change from a nitrogen-heavy NPK formula of 30-20-20 or 20-15-15 to one of 15-30-30. Do not apply the fertilizer at full strength but rather half-strength so you don’t give the marijuana plants a chemical burn. For example, if the fertilizer instructions call for a dilution factor of one tablespoon of fertilizer per gallon of water, mix the tablespoon in two gallons of water.
If you are growing marijuana organically, there are specific fertilizers you can use. I swear by FoxFarms TigerBloom, made by FoxFarm Soil & Fertilizer Company. It is not as strong as the chemical fertilizer mentioned above, so you have to apply more of it more often, but it is a liquid fertilizer that can be used in any growing medium, including garden soil, container growing media, and hydroponic setups. Just follow the instructions on the container.
Maximizing Flower Production
Two suggested methods for increasing THC production or potency in sinsemilla include girdling the plant’s stem with a knife or cracking it with your hands—the concept being that the plant will react to this attack by making more psychotropic resin to protect itself. One problem: These methods simply don’t work. The key to unlocking maximum resin is not trying to make the THC more powerful, but simply producing more flowering tops before the harvest. And that’s why the main methods for maximizing flower production are pruning and topping, limbing, and crimping, bending, and tying-down.
For cutting the marijuana plant with any of these methods, have one set of scissors or clippers for outside and another for inside, and don’t mix them up. It is standard procedure to sterilize them with a flame or isopropyl alcohol each time you use them, but I never did and never had a problem. Do keep them sharp, however, because they’ll cause less damage to plant tissues if they’re sharp. Another alternative is to use single-edged razor blades. More about marijuana and nutrients on http://www.ilovegrowingmarijuana.com