Backyard Aquaponics
A place to discuss aquaponics

Hi,

I've got a bit of a two part query.

I'm just thinking ahead for the warmer weather and what I'd plant. I want to put some tomatoes in, probably zucchini and was pondering a melon or pumpkin too. However my system is still quite young and I don't want to stress things by putting in too many demanding crops. Is there a general 'safe' amount of plants I can put in without making all of them suffer? I was thinking maybe one or two tomato plants per GB, ideally I'd like more but I can't see that happening especially if I do put in a zucchini plant or capsicum or something. At this stage am I best to avoid putting in a watermelon or pumpkin?

Second part is how the system would cope on the fish side of things. I'd be guessing the timing of a lot of the plants going in would coincide with the trout having to come out due to temperatures. How well can a system cope with a reduction in fish numbers and eventual change over to (I'm guessing) fingerlings of a different variety? Would supplementing with a broader range nutrients be in order?

I suppose there would be a bit of a buffer during the changeover because the plants wouldn't be fruiting immediately, correct?

Sorry it's a really long-winded post, I just want to try and get my head around things and hopefully not have things fall apart. I've been lucky so far but I know it's still early days in the grand scheme of things!

Any advice you can give I'd appreciate (I tend to sign off all my posts like that I've noticed, but it's true!) Apologies for the wall of text.

The systems can power along quite well with very little fish.

At this stage, about a week before this shot was taken, I'd just added 40 extremely small Murray Cod (who didn't eat much for a while), but all the growth until then was off 6 goldfish.


All I'd added was the seasol powerfeed & iron. I think it helped boost the system, but I can't be too sure. And until a few weeks ago, I'd never seen a nitrite/nitrate reading. So I wouldn't worry too much.

I'm sure Stu will have some graphs and charts if you want them though.

I'm probably over-thinking it a bit I know, but I just don't want to run into problems with major deficiencies or something down the line. Everything has been going pretty well so far but I haven't been placing many demands on the system in terms of what I'm growing, I don't want it to suddenly bottom out by throwing a bunch of fruiting plants in, but at the same time I do want to grow things, lol.

I suppose should I cause problems I can always yank a few plants out.

Your photo reminded me that I've been meaning to get some of the tomato clips, I'll have to order some now I'm thinking about it.

Thanks for the feedback Col.

I had great growth on that amount of fish, I'm hoping with more fish this season & a more mature system, I'll have even better growth! Every few weeks I poured in a bit of the powerfeed to give it a kick along, and it seemed to have done the trick.

The tomato clips are awesome, and very cheap too.

I totally over planted my system last summer with fruiting plants and payed for it big time with uber K deficiency. I would suggest one tomato per system depending on the size of your system! (my systems had 25 silver perch eating about 40g per day). Its not what you are feeding in young systems, its what you have fed! takes a while to build solids and start mineralising them in the grow beds.

Toms are super nutrient hogs. If you want to go the 'hydro' route and add other nutrients then all this is not such a concern. Blood and bone or power feed should help address deficiency issues.

Like the tom clips - where are they sold?

Thanks Column for the vote of confidence and it may be justified for leafy greens but Ryan is way better on fruiting plants than I.

Last season I had similar problems to Mattyoga but this season I've got more fish and bigger fish so I'll be having another crack. Even so I'll be planting less plants per m2 because at the 6/m2 I had last season even though they didn't grow brilliantly they were too hard to work with because of a lack of space between them.

This season I'm going to go for ~4plants/m2.

When I was suffering my deficiency I did look into finding out, how much NPK each plant would typically need. Did not find any public info, though got the impression there was some proprietary info about.

Dr Lennard has obviously done work on this, and I suspect Ryan must have some system in place judging from how he cranks out fruit frmo his systems with minimal supplements.

Would love to come up with some rough guidelines, eg, 1 tom plant needs 10g of fish food per day to supply its nutrient requirements (assuming all food nutrients available). The challenge is that before obvious visual deficiency with potassium, there is a significant loss of production, so the horse has bolted to some extent if working with visual deficiency signs.

I come to the conclusion you do need to stock reasonably dense if wanting to produce fruit. i.e. lightly stocked systems will struggle, especially young ones. that and go easy on the plants - I found the toms seemed to out compete the capsicum, okra, eggplant for nutrients, so may put the toms in a wicking barrel this year and jack them up on powerfeed.

Thanks for the feedback folks, it's really helpful.

I was thinking I'd maybe be best to stick to one or two tomato plants per system and possibly save the melons until next year. I was considering feeding with Powerfeed and Seasol when they are in, so it's good to hear it's worth doing. I've just been adding Seasol occasionally at the moment but what's in aren't nearly as hungry as fruiting plants are.

My other worry was the period when the trout start coming out and the fruiting plants go in and lack of nutrients, and, well, working out what fish I'm going to put in next, lol.

I was chatting to a friend earlier today about grafting fruit trees and the idea popped up to try grafting multiple varieties of tomato on to the one plant. I know you can graft a single plant onto different stronger rootstock, so maybe it's possible that I could graft two types of tomato together and it work. I'm tempted to give it a go and see what happens as I've got plenty of seeds I can sprout, if it works it'd be handy.


They are an ebay special. I bought them from the seller irainbow, not sure if they are the cheapest but I wasn't buying a huge amount and they were the first I came across. I impulse bought some of these weird stem support clips too, no idea if they are useful or if I'd even bother with them but I figured why not, lol. http://r.ebay.com/KL6c6J

Thanks again guys, much appreciated!

It probably wouldn't be that simple because it would depend on how much vine you allowed them to have. If you had a double or triple stemmed plant it would obviously need more than a single stem plant.
Maybe Xg of fish food per m of working vine?

Ryan has said that uses indicator plants (plants that are very sensitive to deficiencies) and regular water tests to preempt deficiencies.

yeah - I think Dr Lennard first concentrated on simpler crops like lettuce, which are less variable. I've currently got one tom (cherry) thats been growing in the greenhouse over winter. Its now the length of the greenhouse roof (stem length about ~4.5m) with somewhere between 6-10 stems. Had to prop the greenhouse roof up to support the weight.

If you don't hear from me again I've probably been attacked while trying to tame it! Need to get ready for a more vertical sun angle (i.e. summer) so the roof needs to be cleared.

Any idea what indicators for what nutrient? I've suspected malabar greens might be good for iron, though not 100% sure. K, Mg, P and Fe would be great, though I guess different plants may be needed for different temps as some are more susceptible to deficiency at certain temps.

I like that idea, I'll have a read through his posts tomorrow and see what he uses.

*edit* On the subject of my previous double grafted tomato idea, it turns out it's doable with two different varieties and even more, so I'm definitely going to have to give it a go and see what happens. I'd love to have two or so tomato plants growing but have a whole range of tomatoes to harvest.

Foliar spraying in this instance take up the short fall of the system,my first attempts at mixed planting were not very successful,second time around with a spraying program things were a lot better.Foliar won’t take the place of a correct nutrient profile,but if you have say to many Toms or the chillies aren’t showing good growth i have found foliar feeding really does help them considerably.