Grow Box Plants not Growing

by Eric
(California)

I bought the Caddy, which is the cabinet with 2 LED UFOS, and a chamber with an aerated drip system, and a fogger. I got a couple nice plants, about 8" tall. They were in a starter, it's maybe rockwool? I packed them with the rockwool (they had lots of roots) into the clay balls. I washed the balls first.




I got deionized water (my home water was 500 ppm, too high). I got the hydroponic nutrient strength at 400 ppm with Moon Dust. I read lots on this, and saw lots of different recommended levels. For small plants, most recommended around 400-800 ppm. I recently put the levels up to 800. I balanced pH to somewhere around 6.5-7. Temperature has been good. Doesn't go below 70 at night, and 85 in day.

Fans are blowing in fresh air full time. Lights are on 24/7. Lights placed about 1 foot above the plants. So, there seem to be TONS of new leaves growing from the nodes, but they are kinda curling down. And the plant isn't getting taller at all. It's been over a week. Slowly, the bottom leaves have been dying. On the two plants, the lower leaves have been turning yellow.

Help! What am I doing wrong?! I covered the extra plant holes on the lid with plastic to keep the fog inside with the roots. Is this correct?

Answer: Eric- when leaves yellow, it is often because of Nitrogen deficiency. I noticed "Moon Dust" has several different products....make sure you are using one with plenty of Nitrogen (the first number in the N-P-K rating). The most appropriate product they have for your situation would be their 19-8-13 formula, although you will probably need to add a Phosphorus supplement during the fruiting/flowering stage.

When leaves at the bottom of a plant yellow and die, it is either due to under-feeding or to low light conditions. Seems like you should have enough light. Since you were only feeding at 400 ppm, I'm going to have to go with under-feeding. I am guessing you had them at 400 ppm for about two weeks or three weeks. Plants feed less under low light, and feed more under brighter lights. At 400 ppm, you were probably feeding them less than they needed under two UFO lights. Nitrogen is a mobile nutrient, and after a week or two of under-feeding, your plants decided to pull the Nitrogen out of the lower leaves and send it up to the tops of your plants (where it was desperately needed because the tops get a lot of light). This would also be the reason your plants are not getting any taller.

The moment heavy feeding plants, like tomatoes, are a few inches tall, they can take 400-500 ppm. After two weeks, this needs to be increased to 600-700 ppm. By the time they are 8 inches tall, 700-800 ppm should be fine. After that, you can slowly increase the strength of your hydroponic nutrient solution from week to week---simply keep a close eye on the tips of your leaves. At the first sign of leaf tip burn, consider this your maximum nutrient strength for your plants....and you may want to back off the nutrient strength just a little bit at this point.

Whenever you use expanded clay pellets, be sure to soak them for at least 20 minutes first. Otherwise, they do not soak up enough water initially. It is great that you are using a low TDS water source to start with. It is also good that you have covered over the unused plant holes. In my opinion, your pH is a tiny bit high. The maximum number of nutrients are available to your plants at a pH of 6.2 in soil, although hydroponic gardeners often use a slightly lower pH than soil gardeners. Try shooting for 6.0 for a while and see how that works for you.

When leaves curl down, it is caused by one of three things. One- over fertilization (which I do not believe to be the case in your situation). Two- genetics. I have grown two types of the same plant side by side before, and had one grow normally and the other grow with many of the leaves curved down. It drove me crazy, but I eventually figured out that the variety always grows that way, no matter what. Third- temperatures that are too high. This is most likely your case. Ideally, 72 to 75 degrees would be your daytime temperature in the grow box and 78-80 degrees would be the maximum hot spot temp (directly under a grow light at plant top level).

Warmer temps will stress out your plants. You may be able to pull it off (I have grown perfectly fine crops when my grow room temps have gotten up to 85 degrees before). The deciding factor may be whether or not you get mites- mites LOVE warmer garden temperatures, and when it comes to mites the difference between 72 degrees and 82 degrees is like night and day. 72 degrees- manageable and still a good crop. 82 degrees- webs and mites and dead leaves all over the place, and maybe 30% of the produce you could have gotten from your garden.

Hope this helps you out Eric, and Happy Growing!

Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Plant Growth Troubleshooting Questions.

All of the items that I personally use and recommend!

AffordableGarden Design&Setup

(10 week update below)


Find out the cheapest and easiest ways to garden productively in this article.

Hi everyone, Jason from Jason's Indoor Guide here. When I got started with hydroponic gardening more than 24 years ago, my first garden used rockwool cubes and B.C. Nutrients....and I remember thinking to myself yeah, sure, there may be a lot of advantages to gardening with hydroponics, for example there are very few pest problems, therefore very little pest control, no weeding, no plowing or tilling the soil, no soil testing or having to add things into the garden soil, no watering the garden....but for someone who just wants to grow their own vegetables and have more control over their food supply and the quality of the food that they eat, the cost of constantly having to buy grow media and hydroponic nutrients makes this an expensive hobby for most people...


Epic Nutrient Change



I suppose when you take into consideration how much money you save NOT having to buy food at the grocery store, it is surely cheaper to grow your own food hydroponically even with the cost of high quality nutrients. Nevertheless, I didn't have a whole lot of money to work with and I needed to make my efforts as affordable and effective as possible....and in the last 24 years I HAVE learned a thing or two!

As you browse through Jason's Indoor Guide, you will notice all of the systems that I use personally are homemade systems. As I got 3 or 4 years of experience under my belt, I quickly adopted a preference to standing water systems and systems that use expanded clay pellets or lava rock, because the media is re-usable and it eliminates a huge operating expense. So once a hydroponic system is built, garden maintenance is minimal- check and adjust the nutrient solution daily, and to change it completely every 2 weeks....and the biggest operating cost is the hydroponic nutrients. (and the electric bill, lol)...


Homemade Cloner



And, regarding the cost of the nutrients....I experimented for about 3 years with making different compost teas and nutrient teas, but there is still a lot of expense $$$ associated with making high quality nutrient teas....like kelp meal, liquid seaweed, rock dust, bat guano, un-Sulfured molasses, worm castings. You can eliminate a lot of this expense by becoming an expert at making high-quality colloidal humus compost, and use your properly made compost as the basis of your hydroponic nutrient solution.

Unfortunately, I have been gardening for over 24 years and I have only just recently mastered this difficult skill....and even then, only because I happened to find a very easy to follow, high quality technique and decided to follow the instructions to the letter. I produced more high quality compost in just one week than I was able to use in a whole year! If you can master the technique, I highly recommend it. It is one of the top 3 things you can do to increase the productivity of your food production efforts, while at the same time decreasing the amount of effort required to grow all of your own food, and decreasing the total cost of operating your food production system.

And when I say decrease operating costs, I mean decrease them to almost ZERO, especially if you are producing your own nutrients...



High Efficiency
Hydroponics

The ultimate solution to eliminate the cost of your hydroponic nutrients: Imagine a hydroponic system that does not require you to buy any nutrients, does not require you to make your own compost, and does not require you to brew your own nutrient tea. Seriously! No cost and no effort as far as providing nutrients to your plants! Plus, at the end of the gardening cycle you harvest all of your garden vegetables, PLUS YOU HARVEST FISH from the system--->

Aquaponics

Click Here to learn more!

This solution is aquaponics. If you are serious about producing all of your own food and being self-sufficient, this is the ultimate solution for reducing expenses (as much as possible), reducing the total amount of work required, and maximizing the productivity of your gardening efforts. I have been gardening for over 24 years, and it is the perfect food production solution in my opinion.


Produce garnden vegetables AND fish together. Eliminate fertilizer costs!

Besides mastering how to make high quality compost, learning aquaponics is one of the top 3 things you can do to increase your garden productivity, reduce your total costs, and reduce your total work. The product that I learned from is called Aquaponics4you. With all of my hydroponic gardening experience, the first time I came across the Aquaponics4you product I knew immediately that it was something very special! Place an aquaponics system outdoors and use the sun instead of grow lights, and you have reduced every garden expense to nearly ZERO!



The Same System/ 10 Weeks Later!




If you've found this site helpful at all, I would really appreciate it