Help what is this?

Looks like they are maybe getting more nitrogen than they need. Give her a good flush before next feeding and cut the grow nutrients a bit.

 

Looks like a potassium deficiency might need to change your pH in your water fluctuating a little bit allows the plant to get more nutrients pulled out of the soil

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burned tip can be a nute burn and the deformed/discolored leaves are also suggesting a pH/root problem.
what medium?
pH?

 

I would back off the nutes. You've got that plant in a pretty large container of soil which is already loaded with nutrients, and it takes a plant in soil longer to use those up than most new growers seem to think. I don't use any nutes in my grow. We use Roots Organics Original, water and light. Nutes are plant food. MJ is a fast cycling plant. If you grow normal strains (photo) and stay away from the autos (which I've read don't like to be repotted), you can take a clone to harvest in the soil alone. Most of the time, if the plant doesn't become root bound, it's probably not hungry. When they do need fed, you'll see the color of the foliage (new growth) begin to wash out and become a more yellowish green than the rich blue green we associate with a healthy plant. But all during a plant's life, you will see older growth die off. Your leaves are very dark green and that's a sign of too much nitrogen. I start mine in Solo cups, put them in 1 gal. pots when they are ready, and they stay in the 1 gallon pots until they are large enough to go into 5 gallon or 7 gallon containers. The transplant up from the 1 to the larger container into fresh soil, resupplies the nutrients that will feed my plants during the flower cycle. I pot them up a couple of weeks before I plan to flip the lights for flowering and give tap water during flower. The key to getting a good size plant with fat buds is light. Give them the wattage and spectrum and they'll grow hard and produce nicely. But you won't get much of a harvest without it. You can veg a plant with CFLs, but try flowering one with them. You get long lanky plants with under developed buds. They spend their lives searching for light instead of developing like they should because the CFLs just don't have the power to get the job done. Lots of people starting out kind of get the hydro methods and soil methods mixed. The nute markers push their products hard because they're looking for big bucks. But if you use a good quality grow soil, you do not have to put all the chemicals into your plants they would have you believe. I am in no way anti-nute. But you better know what you're doing when you give them, especially know that your plants need them. It's real easy to burn your plants when there's no need for it if you don't get your ducks in a row beforehand. Best of luck. TWW

 

You can use the FF-BB without much concern since it's NPK values are very low. Grow big is usually best used at the end of veg photo (last 2-3 weeks) and beginning of flower photo period. (first 1-2) when nitrogen is being used up quickly for growth spurts. I always cut the recommend dosage in half to be safe. Cheers!

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