Slow release fertalizers aren't the best for growing herb as theres very little control at times like now.Yes you could use a booster.You've got to pay attention to the NPK ratios which are the 3 numbers main number you see on all bottles,packs.Base food have a p and k ratio of something like 4-8,they're all different and most of the boosters are 9/18 which brings the ratio of P phosphorus to 13 and K potassium 26.Some boosters are 50/40 but they ruin the taste of the ganja.The growm dots isn 8.10 so you can give them a pk booster as high as 5/16.You could give them half a dose of something like Dubhas Tree 9/18 the same as Cannas.Less is certainly more when it comes to plant nutrition.Better still use organic boosters as you're using recharge.Make suren you stand your water for at least 24 to disolve the chlorine as it kills the microbes in the recharge.Microbes feed the plant organics but mineral food is taken up dirctly.Guano is great for P phosphorus and also improves the taste and ash is great for K potassium but you need the microbes to convert it so stand your water.Its hard to burn your plant with organics as for the most part the microbes give the plant what they ask for.Its not unlike the job our stomache microbes do.The majority of anit biotics are made from spoil microbes.They also keep the bad guys away.Great for sprayin your plant to prevent mildew and mold,not in flower though.So you'd be better off with bat guano and hard wood ash which you can buy from the hydro store if you wish but it is only ash.Get some hard wood and burn it,haha.