Backyard Aquaponics
A place to discuss aquaponics

We're not sure where to locate our grow beds x 2, we have room under cover and also further out on a concrete slab in the sun. I would like to have one shaded, for leaf plants - lettuces, cabbage, celery etc., and another in the sun for fruiting vegetables like tomatoes, capsicums and chillies.

As we live in a sub tropical zone and do get torrential downpours occasionally, would it be a problem to have a grow bed located in the open? What do other members do with beds exposed to the elements? Is there a problem with flooding, or any other problems I don't even know about yet?

Thanks! I'm grateful for any information you may have.

We have one of our growbeds "outside" in the full sun. There is corn, popcorn and cucumbers planted in it. All the beds that are under cover have shown pretty good germination and growth. The "outside" bed hasn't, I reckon thet it is just too hot and the seeds got cooked. we have had only one corn and 1/2 doz cucs come up and they looked a bit heat affected. We have since put a shadecloth roof over the bed and the surviving plants are looking a lot better.
How is your system going to get the water back to the fish tank? Is it grav. feeding straight back or going to a sump to get pumped back? How big is the tank?
The rainwater should be at a lower pH level so a large amount will effect the pH level in your systems water.(assuming that you are going to try to keep it around 7)
Sorry if I have asked more Qs than answered.
have fun
Axl

thanks axl.

The fish tank will be 2000L and the grow beds will be gravity fed back to the fish tank. We will be using all rainwater in the system.

Regarding the sun growing. I have been a vegie gardener for more years than I care to remember. We generally don't grow anything in summer in the garden, but this past summer grew through the season with shade tunnels over the lettuce and cucumbers. I thought that over the cooler months, my tomatoes wouldn't set fruit without sunlight. Generally tomatoes have problems setting fruit over about 35*, the flowers will form but they won't set fruit.

If you left your grow bed out in the sun and you had a big downpour, would that cause your fish tank to flood, or cause any problems with the system overall? What if we let the grow bed drain onto the ground during rain? Would that cause any problems with bacteria and pH?

We have already had more than 800mm rain so far this year. The fish tank had to get siphoned off a couple of times, but that would have happened even if the growbed was under cover (the tank pokes out a bit).

If it is really a worry for you (that you might not be home to siphon the water off, worry that the fish might get washed out etc) maybe you could put an overflow pipe on the fish tank (similar to the rainwater tank). Have the inlet of the pipe screened to keep the fish in. You could have a drain running to your dirt garden maybe.

The heavy rain might upset the bacteria for a little bit, but if you're running on rainwater anyway, the bacteria would be used to the chemistry. If something like this happened and you were a bit concerned for the state of your bacteria, hold off feeding the fish for a day or two to let them recover.

As jaymie says - an overflow from the fish tank to somewhere appropriate is the go. Remember that you are only going to be collecting rainwater fromt he surface area od the outdoor bed/s - it's not like there is a big area like a roof. If your system is properly bufferred the lower ph of the rain should not cause too many issues unless you have a massive downpour.

I agree also that plants will not thrive in the full sun. My bed is in full sun and although the plants live - because they have a constant source of moisture - they do not thrive. I figure they are expending a lot of energy fighting off the UV. I also had problems with sprouting seeds in the system due to the sun. As soon as the things germinate and heads come out of gravel - I figure they were getting burnt off. Have had no probs with sproutin over last couple of weeks where there has been a lot of cloud cover - though still bloody hot.

Some form of shading is a necessity in summer IMHO.

My system never gets full sun - and I have grown a number of different plants to harvest size... I too get water build up whaen it rains, but this is not a problem as it evaporates soon enough (whaen the clouds leave)

That makes a lot of sense and gives us something to work with today. We're clearing the areas for our tanks this monring and we didn't want to have to move them again. Thanks everyone. I appreciate your help.

Don't forget to take and post pics Forest...

It's easy to work out how much rain you might get collecting in your system from any rain Forest. Pi x radius squared of your growbed, will give you the surface area of your growbed, then if you know your rainfall, you can work out how much will collect over that area..

Or the really easy way, your growbeds are slightly smaller than your fish tank in diameter. If you have one growbed out where it can collect rain and the other under cover then your system will collect a little less water than your fish tank. That is, if you have 10mm of rain, your fish tank will have a water level rize in your fish tank of a bit less than 10mm.. If you have your whole system outside, fish tank and growbeds, and you received 10mm of rain, your fish tank water level would rize a bit less than 30mm... (sorry couldn't be bothered working out the exact sums, to early in the morning )

We've decided to take Jaymie's and VB's advice and have an overflow pipe in the tank. Thanks! Rupert, I'll start a thread when I'm a bit further into it. I am taking photos. We bought the timber for the supports today and will start building them tomorrow. We are full steam ahead.

It's great to have this forum to come to, ask questions and get good advice. Thanks everyone.