Hydroponic using just solar power... What to do overnight?

jef15kersh · Sun May 03, 2015 4:27 pm

I am thinking of designing a hydroponics system that runs off direct solar. Using direct solar, any pump or aeration will only come on during the day. So I guess my question would be what is the best scenario for plants to remain during the time when there is no power on the system? Like should the roots be submerged (no active aeration) overnight or be out of water?

The options that seem most feasible are:
- Ebb & Flow system where at night the bed drains out.
- NFT system that runs during the day and just a little water remains in the channel unmoving overnight.
- Water culture systems either a) floating or b) recirculating
. . a) floating would just run the aeration during sunlight hours
. . b) recirculating would run the pump and aeration during sunlight hours and overnight be sitting in the water.

I am thinking for being able to accomodate the most types of plants a system combining a water culture system with one of the other two might be best. What I wonder/worry about is overnight when there is no movement of the system what is the best state to keep it in?

Kangaroo1943 · Sun May 03, 2015 7:06 pm

I have several ebb and flow units and up until recently had my pump stop at about 6pm, in the late afternoon, ( it gets dark now at 6.15 pm) and not come on at until about 11pm at night, and not turn on again until about 7am in the morning.
I do not have any pumps or aeration on now during night time hours, until the sun comes up at about 5.30 in the morning, and then I still do not commence pumps or aeration until 7am.

I did not notice any difference in plant growth or drop off in fruiting.
I might mention that the conditions I grow these in is outside under my roof eaves of my home, so they can get good natural daylight and sun during the day.

imafan26 · Sun May 03, 2015 8:47 pm

You can turn off the system on a raft or hydroton bed overnight, they can tolerate stagnant conditions for brief periods and plants don't need a lot of nutrients when it is dark. The hydroton or cinder bed will not totally dry out, there will still be water in it but you do want to try to turn it off when the bed is in the drain mode.

jef15kersh · Sun May 03, 2015 8:50 pm

Kangaroo1943 wrote:I have several ebb and flow units and up until recently had my pump stop at about 6pm, in the late afternoon, ( it gets dark now at 6.15 pm) and not come on at until about 11pm at night, and not turn on again until about 7am in the morning.
I do not have any pumps or aeration on now during night time hours, until the sun comes up at about 5.30 in the morning, and then I still do not commence pumps or aeration until 7am.

So overnight your beds are dry... Well, just the residual moisture in the planting medium... No problems. That sounds like a good start... Now to find out about a recirculating and NFT system... I was thinking ebb and flow was going to have to be best bet.

jef15kersh · Sun May 03, 2015 9:01 pm

imafan26 wrote:You can turn off the system on a raft or hydroton bed overnight, they can tolerate stagnant conditions for brief periods and plants don't need a lot of nutrients when it is dark. The hydroton or cinder bed will not totally dry out, there will still be water in it but you do want to try to turn it off when the bed is in the drain mode.

Imafan26, where in hi are you? My parents are in Maui.

Can you explain what you mean turning it off in the drain mode? In the drain mode, isn't it essentially off at that point?

kweb · Sun May 03, 2015 10:24 pm

I'm not sure how much you plan to spend on solar panels but directly running pumps off a small panel will be next to impossible, even in prime conditions.
You may want to look at a deep cycle battery or two to store the collected energy and run off that day/night. Not knowing your scale I'm thinking you will still probably draw more than you can collect so running intermittently will probably work best.

Kangaroo1943 · Mon May 04, 2015 8:26 am

These are some of my Tigeralla tomatoes that are in the system I mentioned outdoors and only get irrigated during daylight hours and don't seem affected in any way.

vitallica · Thu May 14, 2015 4:45 am

If you wish I could design an electrical system with a battery. If you could send me a message about the power of your solar panel and the pump you need to run.

jef15kersh · Thu May 14, 2015 6:24 pm

vitallica wrote:If you wish I could design an electrical system with a battery. If you could send me a message about the power of your solar panel and the pump you need to run.

Thanks vitallica,
I can do the power part fine. Was looking for information on the plant side trying to figure how it could be designed.