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Old 10-23-2014, 04:16 AM
GpsFrontier GpsFrontier is offline
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Join Date: Mar 2009
Location: Lake Havasu AZ.
Posts: 1,855

Hello threedogwrite,
I can see quite a few problems. Before I start it would be helpful if you could post some pictures of the space and what you have going on so far.

First problem,
is (if I'm not misunderstanding you) the method you refer to as the "Kratky" is actually a water culture system that simply lacks the air bubbles. You can grow that way but you will have much better results going the standard way with an air pump.

Second problem,
is your intended lighting source is very inadequate, even for just the greens. Cfls have an equivalent rating, but the actual output your looking for is the actual wattage (not the equivalent). Together you only have a little over 100 watts of florescent lighting. I'm going to copy and paste something I wrote yesterday in case you didn't see it:

I'm trying to figure out which lights I need on which shelves and it what combination.
"As an example of using florescent lighting economically for growing lettuce. You could grow up to 18 butter lettuce heads (if spaced right in 3 rows) with two 4 foot long twin bulb T5 lights (212 watts). At 35 cents a day for 18 hours of light, times 30 days, that comes out to $10.50 a month. If you rotated the crop and harvested three heads a week, that would give you 6 weeks (standard for lettuce) to go from seedling to harvest. Essentially costing $0.58 per head of lettuce for electricity. You can even use three twin bulb T8 fixtures. That would equal about the same light output as the two twin T5 fixtures, and at 32 watts a bulb (x6) be close to the same wattage (192) as the 4 T5 bulbs. But the three fixtures may give more even coverage over three rows of plants. Either way would cost basically the same to run ($0.32 a day for 6 T8's- or $0.35 a day for 4 T5's)."

This is referring to regular 4 foot long shop lights you can get at home depot or lows, no need to buy them from a hydroponics store. The tubes are rated in actual wattage, not equivalent rating like the compact versions. Also that only apply's to the lettuce and greens you plan to grow, and would still be inadequate for fruiting plants.

I just saw where you said this "The lights I already bought are four 65 watt cfl (6400K) and four 42 watt (2700K) bulbs in clip-on dome reflectors"

I need to see what it is your referring to because you may be using the term CFL incorrectly, and actually mean florescent lighting. I don't know any clip in cfl bulbs, and I don't know why you would want to buy a separate fixture for each bulb.

Third problem,
I know you plan to grow small cukes and determinate tomato's, but I'm sure you will have serious issues growing even small varieties in the type and size water culture system. Mainly because they will quickly outgrow it before you even get one tomato. You shouldn't even consider anything less than 5 gallons of water volume for each tomato or cucke plant. Even that will quickly become a maintenance issue. Personally I would only grow larger plants like those using a drip system.

Forth problem,
is 18 inch tall shelves may be OK for starting seedlings, but will be way to short to take lettuce plants to full size. Unless I am missing something in your plans, by the time you account for the hydroponic system and the florescent lighting system will have less than 6 inches of growing space. But again I may not understand tour plans, and pictures would help a lot.

As for the air pump and air stones you refer to Hydrofarm-AAPA15L-6-Watt-15-LPM-Outlets. Looks like a good deal for the price. Going by their rating it should be able to put out one gallon of air per minute from each port. Unfortunately not all air pumps have comparable ratings. I usually get my air pumps and air stones from Walmart in the pet supply's (Aquarium air pumps), and they don't have a GPH rating, only the size of the fish tank, so I cant compare them. But the price at walmart (depending on the brand) is $12-$24, and is only a twin port, not 4 port. The air stones you refer to Jardin Ponds Ceramic Air Stone Diffusers for Aquarium, 31-Grams, look fine but I don't know if their designed to not float (most aren't). The ones at walmart aren't designed to not float either, your supposed to bury them in the rock at the bottom of the fish tank. but I just use gorilla glue or supper glue to glue some metal washers to the bottom to weigh them down. Then cover the washers competently up with pluming goop to water proof it so it wont corrode.
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