Light Cycle for my Hydroponic Garden?

by Terry

I have a 400 watt, 8 pocket hydroponic garden system. I have the clones in there now with a fluorescent light on for 18 hrs. How soon can I put the 400 watt system on them? How many weeks should the clones be on 18 hrs before you change the hours?

Answer: Terry- plants given 18 hours of light or more will stay in the vegetative state. Out of all the lights that would be OK to use, fluorescent lights are the weakest. Whenever I use them to light my clones, I always leave it on 24 hours a day. This will have no negative affects on the plants, and will speed up the growth under the fluorescent light. Once you switch to the 400 watt light, an 18 hour light cycle will be sufficient for the plants and will be less expensive than running it for 24 hours every day (although it is an option).

The clones can handle the 400 watt light as soon as they have roots. The issue is not really the AGE of the clone. The real issue is that the plant is used to a relatively weak source of light, and now you want to transition it to grow under a much brighter light without shocking it. Keep the 400 watt light 4 feet above the clones for three or four days, than lower the light to 3 feet for another three or four days. Finally, lower the light to 2 feet (above the clones) and keep it about two feet above the tops until the clones grow to the size you want.

With a 400 watt light, you get about 12 inches of effective light penetration. This means the first 12 inches of your plants, from their tops down, will be receiving enough light to produce high quality fruits and/or flowers. Growing plants any bigger is usually a waste, because everything under the top 12 inches will not produce much of anything anyway.

In fact, when plants get too big (which is a VERY common mistake growing a hydroponic garden under lights) I end up pruning the lower section bare, leaving just the main stem. I usually do this the first or second week into the flowering cycle. I would rather have the nutrients go up the stem to leaves and flowers that are getting more of the light. This will increase your produce yield in the end.

So, you know you do not need plants bigger than 12 or 14 inches tall by the time they finish. Many plants will grow an additional 50% or so over the course of the flowering period. Therefore, if you want to end up with 12 inch tall plants, you want to start your flowering cycle with 8 inch tall clones.

So, treat your clones in the fashion I described above until they are 8 inches tall. With rooted clones under a 400 watt light, this will only take a week or 10 days. Your question is not about feeding or maintaining your nutrients, so I will assume you know what to feed your clones and how strong the solution should be and how to increase the strength of the nutrient solution each week.

Once your clones are at 8 inches tall, read my page on flower forcing- it has all the information you need for cutting the light cycle and flowering your plants without making any mistakes during this critical stage. Happy Growing!

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(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 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

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--->


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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