Big grow box/trough on balcony - advice?

[Joshua]

Hey all,

Our neighbor is giving us a big wooden trough/grow-box that she made.

It measures 85x50cm and about 45cm tall (outside edges).
We're going to sit it in a sunny corner on our balcony, but still not sure what would be the best use for it.

To grow anything directly in it would require a lot of soil and it would be tricky to water it properly and manage the run-off (Don't want to annoy the downstairs neighbors too much where possible). Already watering can be a bit of a hassle with normal pots, emptying the excess water from the trays into a bucket every time.

So thinking to avoid this.

Otherwise I had the idea to partially fill it with soil, sit some pots on top, and let the roots escape into the soil below.
That could simplify watering: I'd just let the excess water get absorbed into the soil below the pot, but not so much that it soaks all the way through. I thought it could be good to develop trees in.
Could even try some of these tricks that I see people doing with colanders in the ground.

Could that work for tree development?
Any other suggestions/ideas?

Worst case is that we just sit some pots inside it so they get some shade and wont overheat in summer.

Just to note also that I'm competing for balcony real estate with my other half. She's starting a container-grown cut-flower project and in general just wants more flowers, so we'll surely be sharing this box

[Matt S]

Hi Joshua,

Have you thought about a wicking bed? They are a great way to control watering and there's little run off. I use them for veggies and small trees and they love the consistent moisture.

Matt.

[Joshua]

Have you thought about a wicking bed?

First I've heard of them, looks interesting though! Might have a go at one, a bit of research to do now
Thanks

[Joshua]

a wicking bed

I'm liking this idea. Looks like a fun little project.
Plus there's a mention on this thread of wicking beds allowing "close to maximum" growth.

I'm sold .

I like the idea of having the drain pipe low but on an elbow joint you can turn up.
And looks like you can choose to top-water or bottom-water. Perhaps good to flush out the soil from time to time but some have said that there's a risk of letting to much organic stuff and nutrients in the reservoir which could lead to stagnation.
Could that be a concern?

Regarding choices of plants, I'm guessing that since it's pretty damp all the time it's better for some species than others.
Would some of those thirsty natives like callistemon, eucs, mels, do particularly well?
And not so much things like pine or rosemary?

My chili and basil seedlings would go really well in it too when they get going I think..

Some people mention that you have to be careful about the kind of soil. Would a fairly standard potting soil work? I've found a peat-free one that uses coco coir I think. Seems fairly light.

I think I can find an equivelant to Scoria here ("Pouzzolane" they call it). Would I need to be careful about the grain size or would it be porous enough to wick the water?

We put it in its spot today, here's a photo for the record

balcony_grow_bed.jpeg

[Matt S]

I don't have any experience in growing pre-bonsai material in wicking beds, but I have citrus trees and a Quince and they've been happy for many years. I've also found that the commercial self watering pots you find at hardware stores are really good for developing Trident Maples, so they would work well in a bigger wicking bed.

Once your plants are established they should pull up the water quickly and stop it from getting stagnant but you should still give it an occasional flush. The elbow joint is a great idea and you it allows you to check on the water quality.

I've just used a good quality potting mix in my half wine barrels and a loamy garden mix from the local landscape supplier for the larger veggie beds. Pouzzolane looks good, but wash it first otherwise the dirt will settle and create an anaerobic layer.

Have fun!

[Joshua]

Took me a while but I finally got everything together. Finished it on the weekend.
Decided against the adjustable drain at the bottom, proved to be too complicated and didn't want any risk of leaks so opted for a simple drain at the top of the reservoir level. Figured I can just siphon the water out if I ever need to drain it.
And to check the water level I put a cork on a stick, and that sits in the water inlet.

In the bottom I just used those clay balls (the ones they sell for 'drainage') plus a few strips of felt for a bit of extra wicking power, and some pvc tubes to hold water.

wicking bed before soil.jpeg

Thought of the idea of making it also a vermicomposter and it looks like some people actually do this. So I set up a worm tunnel in the middle. Just a 100mm PVC pipe with some holes in it.
Still hesitating about actually going through with it. Worried that some might escape down into the reservoir.

wicking bed planted.jpeg

On the left there's a lemon after a prune and root-prune, in the middle couple of basils and chilis, an e. camaldulensis seedling on the bottom right, and some lemongrass on the top right.
The very top of the bed makes it 30cm deep so should have probably added a bit more soil.

[Matt S]

Good job, your plants will love it. Keep an eye on the Eucalypt, it will fill the container pretty quickly and out compete everything else!

Matt.

[Joshua]

Thought I'd post an update of how this went. Need to start thinking about what to do with it this year too.

The chilis absolutely took over in terms of aggressive growing. Everything else still survived, and did pretty well actually. Only toward the end of the year the Euc managed to catch up and overtake, which made for a very sparse lower half and a bushy top.
I probably had too many plants in there, even though they all seemed to thrive. Will try to be a little more cautious for over-crowding next time.
Otherwise I noticed the geotextile where it was sticking up out the sides was actually degrading pretty bad. I'm hoping it's just because it's not UV resistant and that under the soil it's still intact.
The tube to feed the worms got filled pretty quick so I added a couple of pots that sat on the surface, and this increased the surface area to which I could add kitchen scraps and cardboard. Still need to add very slowly.

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July before leaving for a long holiday.

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August. On the left there is another experimental self-watering bucket with a couple more chillis.

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September. It started getting a bit ridiculous and hard to get a photo.

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November.

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Today. Chilis cut back to stumps. Lemongrass looking like it died, not keeping it. The basils were pulled out. Just the Euc and Lemon left. The lemon was cut back a bit, but they'll both be trunk-chopped soon enough.
I think the chilis survived winter and are going to start shooting back. But I'll be digging them up because this year we'll be trying some Peter pepper seeds that I was given.
For now the bigger chili stump (and lemon) is being used as a support for the euc which will almost completely fall over otherwise (I haven't bothered to stake it at all).

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Here you can see the bushy top of the Euc, leaning over the lemon.