They try to make it simple.... and you make it complicated again You can use a Periodic Table and calculate the molecule weight per Mol and therefrom calculate specific amounts aka number of molecules per Mol/weight devided by the weight of the pack etc... Fim

Aloha,

in my led box it is signal of low phosphor.

Tips of fan leaves clawing downwards is one of the classic signs of Nitrogen toxicity. It's not too drastic unless the leaves begin to yellow, starting at the very tip. Other Pictures above Show edges Curling upwards. That is classic sign of heat stress. You describe that your plants are already X-number weeks in flowering and you are still giving Guano and other Nitrogen-containing additives.... That may be your Problem. Generally, when flowering starts, that is when Nitrogen feeding should be cut to a Minimum, and the feeding for flowers should be slowly increased (phosphorus, topping micros, etc.). Also at the Switch-over to flowering, it is sometimes advisable to perform a flush to clean-away the excessive Nitrogens and the unwanted salts that have accumulated during veg, so that the flowering Phase can begin afresh. Overwatering (which can lead to root-rot) sometimes Looks like N-toxiccity. Be sure to allow the soil to dry a bit between watering. MJ roots Need to have Oxygen... You are in soil, so you don't Need to Keep adding so much Nitrogen anyway. The soil is your buffer and most likely either has already or retains more than enough Nitrogen for the plant. (If this were a hydro-grow, then you would have to be more attentive to keeping Nitrogen/Nutrient Levels exact.) I suggest for you to do a bit of reading about the LifeCycle of MJ and the nutrients that MJ Needs at the various stages of its life. Such Information is available at many places in the Internet. The Servers and Providers of these Informations change from time to time, so I don't have any direct links for you. But you will find a wealth if Information when you perform reasonable searches. Do the Research. You will be richly rewarded for your efforts. Search for things using many combinations of search words like: super soil for marijuana, nutrient requirements for marijuana, importance of pH for marijuana, pH and nutrient uptake for MJ, search using your own words, be creative, and don't give up. Along the way you will certainly discover other words and word-combinations that yield even more Information. Sometimes some answers can be found by searching similarly on Youtube. Give yourself time to search and absorb the info. Have fun while doing it. I know that I did. Also there is an excellent library of Information on the diseases and pests for MJ. Search for it under "diseases of marijuana". You may find several different Versions, many with Pictures included. Each time you find Information that is especially useful, download it if it is possible OR copy and paste it into your WORD document and save it in your own library on your PC or on a Memory stick, so that you will always have that Information at your fingertips. Good Luck, Have fun. Really... By the way, if you havent seen it before, a rather fun presentation of how to create a homemade hydroponics Setup is found on Youtube. Search for "Mr. Green" and "I Grow Chronic". 13 Chapters Long, each about 15 minutes. And entertaining.

I had that problem when I put too much feeding( leaf become crispy, not so soft anymore) and then PH was too low...because of N.. EC pen in operation??? Any pics...? Keep Growing!

Could be a Calsium problem. It's so hard to know what growers done up till the problem they want help with. This is why it's so importend to make a grow journal in the forum so we all can follow step by step.

How i wish helping growers would be as easy as to help myself. Could be many reasons and very hard to help without a background story on what you done up to this point. Usually when a flower turn yellow a few days after flowering it´s as simple as. To Much water OR lack of right feed as in nutes.

There was another similar question, I responded to earlier. There can be many reasons why your plant leaves turn yellow: 1. Lack of sunlight. If your plants don't get sunlight at all, you should consider repositioning them. Like in humans, sunlight is an important factor in the growth and developement process of a plant. 2. Root issues/nutrients. You should try checking, if you'd need to add fertilizer or repot your plants. Sometimes the roots get too compacted within the pot and this can also lead to oxygen issues and the roots sticking out from the bottom of the pot. 3. Too little water. Self explanatory. 4. Insects. You could try and look if there is a pest problem on your plants and maybe use "Neem Oil" (I never used it myself, but it's from a sout asian tree and completley natural pesticide).

Do you have enough soil in there? Did you overwater them (or: do the roots get enough oxygen?)? Try putting scrumbled eggshells around your plant (basically adding nutrients). A friend of mine had a similar issue (slightly dry&yellow - ish leaves) and this fixed it for him.