couple flood and drain questions

hey guys, im wanting to switch from growing in sunshine4 mix in netpots/bed to flood and drain tables. Ive never done it, so i need a few pointers. i have beds built already, one is 5' x 14', and the other is 4' x 8'. Can i just easilly convert these to flood and drain tables? line them with thick poly and add a drain to one end? or would i be better off braking the big bed into smaller beds?

and as far as growing in them, can i just start my clones in small rockwool cubes, then stick them in 4"x4" cubes (or bigger? 6"x6"), then place them in rows in the tables. I was thinking of covering them with white/black poly with slits in it for the plant to poke through, so the root system stays in the dark. then all i need is a big res (for the big table), smaller res for the 4x8, and i just place a pump in the res(s) flooding the tables periodically?

heres where im lost, how often would i need to flood? say, run the pump for 3 mins every 6 hrs or so? I mean, the rockwool cubes will be easilly saturated when the bed is flooded, so how often would i need to water?

and as far as feeding, say i would be starting new girls out, would a 400 ppm solution of veg be sufficient, then slowly increase to, say 8-900, vegging for 2 weeks or so? Iid be looking at doing a sea of green type grow) then change all the water in the res with bloom, and start them out at 7-800 of bloom, and go up to 1000-1200 (depending on strain)? changing the water weekly, and checking ppm daily?

i wanna try flood and drain water system for my next round, at least in my one smaller room, in the smaller bed. at least just to get a try at it.

is that about it?

Flood and Drain/Ebb N Flow are great systems and i use a modified version myself. To answer your question, i have a rubbermaid container with ten gallons of water in it mixed with my nutes. I cut holes in the lid and placed nets pots where i put the plants. I then put a pump into the res and hooked a cpvc drip system. I ran the drip system 24/7 once the plant develops its second of leaves.

As for the PPM- You wanna wait AT LEAST two weeks after sprouting before you even think about adding nutes. Seedlings can grow and feed off what they have inside of them until these develop there second set of leaves. After these two weeks add you nutes at 200-250 ppm for 1 week. You can then go up to 400-600 ppm. Once you see your plant developing calyxes you can up to just under 1000ppm. Once your plants starts to flower this is when you wanna kick it up to 1200-1600 ppm.

*****REMEMBER THIS***** Very seldom do you see a plant in a hydro system die from LACK of nutrients. Very often do you seen nutrient burn from having to much. This chart will help, follow it exactly and i promise your plants will grow. Make sure you keep a discrete tab of what mixtur of nutes you are using. That way once you get going you can switch them up to see what works best. keep track of how your plants react to certain mixtures until you find the perfect one. REMEMBER, dont go crazy with the nutrients!!!!

One of the reasons hydro can be so much more fruitful, especially in F+D is the increased oxygen to the roots. Oxygen is pulled over the root ball during the draining process. Using the the large rockwool cubes detracts from this process as the rockwool retains alot of water and stops the oxygen being drawn across the roots. Feeding can be a bit more difficult as you can potentially, especially when the plants are young, drown your plants.

I personally use hydroton. Drop your clones (1 inch rock wool cubes) into the hydroton and top feed for the first few days in conjunction with F&D until the roots reach the flood level. This way it is impossible to drown em, I feed every 90 mins for 30mins during light on and not a sad leaf or plant to be seen.

without doubt the most important thing in hydro is PH, let the ph stray too much and problems arise quickly. Maybe consider a nute range with a ph buffer, I use Dutch pro which is a cheap 2 part. Veg and flower are cheap but Explode (booster) is pretty expensive but worth it. if your lucky like me, the buffer brings the ph bang in line without adjustment. ALways remember that less is more with your nutes. Come in low and build up, don't try to smash em with high doses, your risk burn and stunting them.

Hope this helps.

Thanks for the info guys, but i also asked if i could use the beds, as-is (size wise) or should I break it down to three smaller beds (the large one) again, it measures about 6' x 14'. Its built with plywood bottom, and 2x4 sides. The smaller bed is 4' x 8'. Im looking to get as much info together, and get all the stuff needed together so i am ready to do a run on my next run (about 9 weeks). I plan on doing a water run in the smaller room so IF i screw something up, its not too much of a loss. How big of a res would i need for the 4 x 8 bed? I was thinking it would be easy enough to do a grow using irrigation lines an drip emitters, feeding from the top, a im using 5" net pots already, all i'd need is some rockwool cubes, and some lava stone, or whatever medium to fill the pots/support the plant, something like this?


sorry for the crappy illustration, but it gets the point across.

To complicated with the top feeders. The more pipes, sprayers etc means increased chance of leakes, blockages and associated problems. just pump your water uo through the bottom of your tank overhanging ya res. Nothing can leak or get blocked, fool proof...ish. When your plants are young and your roots dont reach your flood level just top feed by hand once a day for 2-3 days. Keep it simple.

MrMeanGreen said:

To complicated with the top feeders. The more pipes, sprayers etc means increased chance of leakes, blockages and associated problems. just pump your water uo through the bottom of your tank overhanging ya res. Nothing can leak or get blocked, fool proof...ish. When your plants are young and your roots dont reach your flood level just top feed by hand once a day for 2-3 days. Keep it simple.

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very good. this will be my method of grow then! thanks

No worries. I am based in the UK and no doubt have a different set of issues to monitor over our American friends. Keep ya ph good, and go easy on ya nutes. PM if you need any help.

Personally id want a deeper bed than the 3.5" 2x4's on top of plywood offer.. id go with 2x6's or 2x8's.. just my .02

Also, pertaining to rez size for the 4x8, botanicare says their 4'x8'x8" flood tray holds 80gal. Just a refrence point fer ye!

bazookajoe said:

Personally id want a deeper bed than the 3.5" 2x4's on top of plywood offer.. id go with 2x6's or 2x8's.. just my .02

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Didn't see that bit. If 3.5" is total depth then I agree..... to shallow. Ideally you want the freedom to go 4-5 inch if needed. With regards to dimensions of bed, it depends if your doing big fella's, scrog or sog and what lighting / wattage / shades yr using.

You could break ur other bed down into smaller beds unless u got a 250+ gal rez sittin around, 3 beds, 3 rez's and 3 1kw. Just an idea!

very good guys! I can easilly use 2x8's and build three small beds in the one big bed. piece of cake. then i could use three smaller res's, one for each. i believe this would be easier to control than one big res. I can see it coming together pretty easily. thanks for your input!