So right now you need to make sure that they are getting Nitrogen and Phosphorus. If you can get to your plants you can feed them once a week if the soil is not soaked the whole week through. If your plants are soaked then mix your ferts totally concentrated and drop half a cup or two on tom of the main stem. I really hope you get something that has some K or potassium in it. Any plant like MJ that has a healthy feeding habit and heavy flowers has to have lots of K, things like corn. SOmething with the ridges on the stem.. something about that type of plant loves P and K. Good luck with your flowering. Its not to late to hit the gas with a feeding regimen if you are happy that your plant is going to have at least a few colas to harvest.