Grow Lighting Distance

by Mark
(North Carolina)

I'm using "My Best Hydroponic System" and would like to know how far above the plants the lights should be for optimum performance. I have 2- 400 watt HPS grow lights back to back, but only have ten plants in the middle of that 36 plant system. Needless to say I am a first time grower and would appreciate any insight you could give me. Thanks for your patients with us beginners.

Answer: Mark- I would position the 400 watt lights 12 to 18 inches from the tops of your plants to the bottom of your lights. The hydroponic system you are using is 4' x 8'. Imagine the space as two 4' x 4' areas side by side. One light should be positioned in the center of each 4' x 4' area. Your biggest concern should be the temperature at the tops of the plants directly underneath each light.

An indoor/outdoor thermometer with a remote probe is an invaluable tool for this, and some brands (like Sunleaves) cost as little as $25.00. The next thing you want to pay attention to is the temperature of the rest of the air in the grow room- keep it as close to 70 degrees as possible. Usually, the farther above 70 the temperature goes, the more problems you will have with your garden (especially if mites or other indoor garden pests were present to begin with). With an indoor/outdoor thermometer, the indoor part can keep track of the grow room temperature while you place the "outdoor" probe in your hot spot (directly beneath a light at plant level).

My only other suggestion would be: if you are only growing ten plants, and they are relatively small plants in nature, you should be able to use just one 4' x 4' side of the hydroponic system (half of the system) and only need to use one of your two 400 watt lights. The key is having your plants fit into the 4' x 4' area, because that is the very maximum area a 400 watt light can illuminate effectively when gardening sun-loving plants (which would include most garden veggies, herbs, and flowers). Hope this helps you out, and 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...

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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!

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