A few questions on flood and drain systems.

[Alex]

How often should a grow bed, flood/drain? I know I read in the book it says with timer systems it should be timed on for 15 minutes every hour. But what are the specifications for a flood and drain?

Also, I have 8" of 'wet zone' in the bottom of my grow bed along with 2" of 'dry zone' on top that does not get flooded. How do I start growing plants from seeds now? I have 2" rockwool plant starter cubes and I was thinking to position them just so the base gets touched by the water at peak flood? Or should I keep them in the complete dry zone and water them each day until their roots reach the peak of the flood in the grow bed? Or can I just leave them in the dry zone and have it all work on its own?

And one last thing, where should I place the hose that pumps water into the grow bed? Should I put it below the 'dry zone' so it keeps that zone, dry? Or should I attach it to a sprinkler like system at the top to get all the plants wet? This makes me wonder though how the top zone could be considered dry if water is constantly being poured over top 24/7.

Thanks in advance, I am almost done with my system and I think so far it is looking fantastic! It is a miniature, 20 gallon growbed, 10 gallon tank, and 14 gallon sump. I will soon be putting up pictures and videos when I get it functioning.

[Alex]

Excellent! Thank you for the advice. There wouldn't be anyone that happens to be familiar with growing cilantro? If so maybe I could get your flood/drain per hour or how often you soak the roots.

I'm going to do exactly what you have suggested and put a bypass to the FT. What would be a decent turn over then for a small setup like mine? Or a better question, what would a maximum aggressive turnover be if 1 per hour is a minimum passive? Also I'm hoping I can keep enough flow to let the bell siphon kick in without having to flood/drain so many times an hour.

[Harold Sukhbir]

Hi Alex,

There are a host of factors involved with selective crop growth. I always experiment with growing conditions of individual species. The type of fish food, the humidity, the light exposure, the cycling time, the Ph, nutrient supplementation,etc., are just some factors which affect plant/fish growth. I've grown cilantro with fair success. Strong seedlings give a good plant. I start them in potting soil in heavy shade, water with system water, progressively exposing them to direct sunlight, until they are 2-4 inches high, before planting in AP. As for the cycles.......experiment. Aim for 1x to 2x per hour and observe the plant growth/roots

[Alex]

I have good news! And I have bad news...

The good news is, I have installed the bypass hose to better regulate flow to the grow bed. This has helped me manage 6.5 flood/drain cycles per hour.

The bad news is, I don't know how else to get the cycles per hour down without downsizing my bell siphon!

The cloudy news... I have an idea. I've noticed the water flow into the grow bed comes to a halt when the hose is submerged and the water flow is not strong enough. This leads me to believe I can manage to get the cycles down about 1-3 times per hour leaving me with a 5.5-3.5 flood/drain cycle per hour! As well, there is another type of valve I can purchase at the store that is much more accurate. This may allow me to bring down the cycles by 0.5 or so.

So with any luck I may get the flood/drain cycles down to 3 per hour which I think would be fantastic for starters.

Please! If you have any advice let me hear it. If worst comes to worst, I will purchase a new 20 gallon long tank, drill a new hole, and create a smaller bell siphon. This should allow me complete control over the cycling to around 1-3 per hour, judging from my current situation.

Anywayssss, I've personally come a long way from a plastic green tote purchased as my grow bed that never had a top dry zone. Plants grew fairly well for the two weeks I had it set up, so with my current system I am very excited to see the new growth.

[Harold Sukhbir]

Hi Alex,

You can place a reducer on the down pipe in the bell siphon. If the pipe if a 1 inch pipe you can place a 3/4 inch internal reducer into the pipe. You can place a 1/2 inch reducer into the 3/4 for further reduction. If this obstructs the bell in any way you can reduce the exit end of the down pipe instead. I've also used clear plastic tubing as a reducer for a bell siphon as well. However, If you observe that your plants are growing well at present, you can leave the cycle times the way it is/was.

[Alex]

I currently am using clear tubing as a test for the down pipe like you have said, it's how I achieved a lower cycle time. However I think when I get off work I am going to purchase a reducer and a half inch pipe for the standpipe instead of the current 3/4. This should allow me to use an even smaller tube for the down pipe from what I understand. The current 1/2 inch tube down pipe is as small as I can go while still being able to get enough suction for the 3/4 inch standpipe.

Soooo I am thinking, standpipe/downpipe reduction to 1/2 inch and seeing what that will do for me. If the cycles still aren't low enough I can probably fit a 1/4 tube on the down pipe to achieve a better time.

[Harold Sukhbir]

[Alex]

So I took the pipe leading to the growbed out of the media and have it just fall onto a scratchy pad now. It dropped my turnover time to 4.2 times per hour. (: for right now I think I will keep it like this and work on a new concept growbed with a 1/2" standpipe for precise conditions.

[John McCaw]

ALEX;

I like what has been said, and Harold has a good point about your turnover rate. I opted for a "T" split on my pump line, returning water BACK into the fish (or sump tank, as I have). It can be set up to "drop" back into the tank, providing O2, and will allow the line to you grow bed to be controlled with greater ease. Also, by teeing it, you provide an additional line for expansion down the road. I have 50 gal rubbermaid tubs with crushed pee stone, and I just sprinkled seeds right on top, and have a nice bunch of happy plants. For more direct planting ( such as for beans) you can use the old grade school trick of placing the seeds between two sheets of damp paper towels. Place it in a gallon zip lock, with just a small opening, and place it in a warm place where you can see it each day. When the roots get about 1 - 1 1/2 inch long, carefully place them in the grow beds so that the roots are reached each time the "flood" comes in. It works wicked good.

[Alex]

Thanks for sharing your input. Currently my bypass line goes into the sump as well to make things easier on the eyes. I think I am going to make a little nursery area and use my old square led light above it. Dropping these seeds in the hydroton worked for about 50% of my plants. The others roots get a little lost and start to dry up. I'm going to be using rockwool after this batch of plants because it's much easier for me to identify what is going on exactly.

[Alex Veidel]

Is your problem that if you slow your flow down, your bell siphon won't trigger? You could always put a reducer on the stand pipe, that way it takes less water to trigger.

Alex said:

I have good news! And I have bad news...

The good news is, I have installed the bypass hose to better regulate flow to the grow bed. This has helped me manage 6.5 flood/drain cycles per hour.

The bad news is, I don't know how else to get the cycles per hour down without downsizing my bell siphon!

The cloudy news... I have an idea. I've noticed the water flow into the grow bed comes to a halt when the hose is submerged and the water flow is not strong enough. This leads me to believe I can manage to get the cycles down about 1-3 times per hour leaving me with a 5.5-3.5 flood/drain cycle per hour! As well, there is another type of valve I can purchase at the store that is much more accurate. This may allow me to bring down the cycles by 0.5 or so.

So with any luck I may get the flood/drain cycles down to 3 per hour which I think would be fantastic for starters.

Please! If you have any advice let me hear it. If worst comes to worst, I will purchase a new 20 gallon long tank, drill a new hole, and create a smaller bell siphon. This should allow me complete control over the cycling to around 1-3 per hour, judging from my current situation.

Anywayssss, I've personally come a long way from a plastic green tote purchased as my grow bed that never had a top dry zone. Plants grew fairly well for the two weeks I had it set up, so with my current system I am very excited to see the new growth.