Filling raised bed for avocados

Manfred says...
What you fill it with depends mainly on where you are. What sub-strate you have would influence the decision if you have lots of different choices locally. How deep is it?

sternus1 says...
A little over 1m deep. I'm on the worst cracking clay imaginable and none of that can go in obviously. I have plenty of bush type materials that could go in but most of it is aussie hardwood which has allelopathic properties, might not be a great idea.Have a fallen pine tree I could hack up though if that's vaible--what kind of PH do they like?

BK when you say holes the side, are yours drilled out with a large bit or did you use a boring bit? Like what diameter are the holes, just small or larger? Also I need something to line the bed with to help preserve the wood--any ideas?

Feet is easier than typing 396.24 centimeters lol

Manfred says...
I'd go with Bangkok on this and fill at least the bottom third with some sort of crushed rock, just not shale or sandstone. Pumice would be great, if you live near enough a beach to collect about 2 cubic metres. You can put a bag or two of gypsum down first, but after you start regular watering your clay will close up and never reopen, so much of it might be wasted.

In most areas you can buy a reasonable garden mix and/or a reasonable potting mix by the cubic metre. I have had some success interlayering that sort of stuff with spoiled hay in raised beds, but because you are looking at a longer term I wouldn't use that. It does eventually subside and need topping up, which is OK for veges but probably not for trees.

The garden soil mix might seem a little heavy at first, but it does last. Top up with potting mix as a mulch and keep it topped to planting level over the life of the trees.

I wouldn't use any uncomposted stuff like timber or woodchips. Avocadoes are too touchy to risk it.

I hear all sorts of horror stories about avocadoes, but I also see them growing where they probably shouldn't.

Bangkok says...
First you need to make the place on a slop, 1 cm a metre is enough..make sure the water will run far away from the tree.

Then make sure the soil doesn't stay too wet so mix it with sand/charcoal/charred ricehusks or whatever charred material.
Pumice or perlite or something similar is also perfect. (My bed doesn't have that though)

I threw huge bags of leaves, grass, compost, cow dung in my beds and put EM on it, that's all.
The worms will love all that and also dig into the clay to make it more open. If you find worms then throw them in the bed. Also never walk on the soil in the bed.

The winter in Brisbane is the dangerous period so use bi-potassium phosphite or something similar against pytophtera. Don't water in winter unless it's really dry.

My experiment with pumice is in huge pots. It isn't cheap but also not very expensive for big bags. Perlite costs much more.

The key is drainage and slopes. I also had other plants next to my avocado when it was young so they would help drink water and keep it dry. You can use beans who also give nitrogen to the soil. When the tree is larger you pull the beans or other plants out.

echinopora says...
My successful avos have been on mounds of aged, rain leached manure and mulched palm trash mixed with some graded 2-3mm blue scalps. The palm trash is basically like extra coarse orchid coir and I found that the avo's didn't like manure that was less that 6-12months old. And lots of shade. I think lack of protection from sun and wind were the main things that killed my first 2. My secondo has made it over a year now so hopefully it keeps going.

Bangkok says...
From left to right in the raised bed:

1- red pearl wax-apple (chomphu mook daeng)

2- cocktail mango tree

3- in the corner is the cocktail avocado

4- cocktail chomphu waxapple with a small eugenia candolleana in front of it.

5- Durian mongthong (behind the fiji longan but you can't see it on this pic)

6- on the right in a big pot you see my fiji longan after pruning

Straight through the lawn are underground canals made of course sand. They start in the middle of the raised beds and go to the lowest point of the garden onto the driveway.

In the walls i left some openings and drilled some holes. The underground canals go under the bedwalls and that works well.

The raised beds are made of those curved stackable bricks which i filled with cement so ants don't nest in them. Also i used cement to connect the stones.

Also i have sprinklers in all beds and pots.

I prune my tree's regularly because it's a small garden and i want to grow many different fruits.

The bed is waterlevel so you can see the slope of my lawn. Also the clay floor in the beds has a slope.

I made this design because i had many circles of those curved bricks left. They are in different diametres like 70 cm, 120, 200, 300 cm.

The simple way is to just make circles of those bricks and you can make it as high as you like. The topbricks are flat, the others have a profile so they hookup into eachother.

Since i made this many neighbours also copied it. Those bricks cost 2 for 1 au$. Oh i also made them waterproof with a chemical so they don't stay wet all day and get green and dirty. You do that after bricklaying with cement. If you don't use cement then first make them waterproof and then stack em.

Pictures - Click to enlarge
Picture: 1

Bangkok says...
Tomorrow i will put more pics, i have plants all around the house but since i live in a hi-so community it has to look nice although it's an orchard.

My lawn is also on pure clay and now it's wet season but a very very dry one. This lasts untill december and then we might have no rain at all untill april/may.

I don't water the lawn though because then i have to mowe it more often and it's 34 celcius in daytime. Even grafting makes me sweat like crazy.

But slopes are very important, also for a lawn. When i didn't have decent slopes i couldn't walk on the grass or i would sink into the clay and kill the grass.

I will also show the planters i'm building, i got the wrong tiles from the shop though...oh well this is thailand, i'm used to things going wrong haha.

I hope the avocado will flower soon though, the tree is big enough for it. I don't give it any nitrogen anymore and it's also on a water diet.

Bangkok says...
Thanks Marc, i was going to spray the mango with zinc/boron today but it was too hot, so i 'll also do the avocado then.

I have dolomite and epsom for magnesium, can i also use those?

My mango has big cracks in the stems and the leaves are crispy so that's boron deficiency i read.

No idea how the Thai do it but they can make very small avocadotree's bear fruit, i saw one last year which was 40 cm tall with an avocado (hass according to the vendor but it was round shaped). I also have that variety on my tree now.

And yes i also like Balistyle and am still looking for more balinese artifacts.

There are huge closed community's in BKK built in Balistyle but ours is in European style.

I will show the rest tomorrow, i have more of that style.

Bangkok says...
Yes they sell 2 kinds of gypsum in the gardenshop, i don't know the difference though. One is white and they other more yellowish. I will buy it.

I use osmocote slow release fertilizer since this year but that's not cheap.
If it works i also don't know yet. Now there is a cheaper version of slow release from Israel, takes 4 months to melt, think i 'll try that soon.

We have glassfibre-internet since 2 days and can watch online tv, i will search for that ABC program if i know which remotes to use.

I just ate a thai grown avocado with my dinner, it was good but hass is the best. Last year we had huge avocado's here, round ones. I guess this one is the same but it was small like a tennisball because of the severe draught i figure. Last year the round ones were 4-5 times bigger.

I also grow hass (scions from Spain) but not sure if it will fruit in my climate. Well i just try it out.

Markmelb says...
Mike - not talking about using alot of Gypsum - maybe 2 handfuls dusted around a 2 to 3 year old Avo say 1.8mt tall once a year - Avos love it as is like a fertliser to them and doesnt acidify soil as Avos like Acid around 5.25ph - look at Growquest videos on youtube to see how he uses when planting.

Mike Tr says...
Mark That isnt too much but some people go overboard with the stuff.If anyone has used either to break up clay successfully ever it would be good to hear about.I doubt this is the case but you never know.Deep ripping with humus and heavy C content additives tossed in might help a bit with clay but hummocking and planting top might be a better option.

Bangkok says...
Yup sternus, they are perfect. My dad has thousands of those bluestone spalls and made huge planters of those, walls from 2 metres high along his driveway as well. They don't come cheap though in Europe and can be very old.

They cost 5 euro a piece in the gardencentres in Holland to give you an idea. My dad bought those stones from a whole road in Amsterdam (very cheap) but had to get them out of the street himself (read let me do it for him).

He just stacked them but after some years those walls start moving so he had to put cement between them. His beds are very high though.

Yes just be creative and build something original.

mc2 says...
What’s the minimum raise bed size (length & width) to grow A & B?

Fruitylicious1 says...
Hi mc2

For two avos, minimum L=6m, W=1-1/2m, H=1/2m. Minimum 3-4m between semi dwarf varieties, 1m away from the edge of the raised bed. Anyway, you can play with the figures if you want.

Happy gardening :-)

David01 says...
Hi mc2,

I have 5 grafted Avocado trees, Hass, Lamb Hass and Pinkerton and few small seedling for future grafting. All type A. If you want to grow Avocado successful then I suggest you to grow it in a fabric 50l not plastic pot for a couple of years when it get to 2m then move it into the raised bed. In the pot you can move around to protect it when it young from winter, sun burn and gusty wind and root rot etc.
As I understand in cold weather like Melbourne you don’t need type B as there is a time overlap between the Male and Female phases, thus you still get around 60%-80% of fruits if you don't have type B, which is more than enough. Cheers.

There is one very good article to read as below:
http://www.petethepermie.com/wp-content/uploads/2012/09/Avocado-so-easy-to-grow-in-Melbourne.pdf