Backyard Aquaponics
A place to discuss aquaponics

I used the trench and hill method this year and I took this photo of a cross section of one of my spud beds while I was harvesting. Thought it might shed some light on how potatoes (mine at least) send out tubers in the soil substrate.



Undoctored photo.



The seed potato was put in the bottom of the orginal trench and then back filled. All the tubers grew under the original back fill line and none in the hilled up section.

In saying this I had a very dry July this year and maybe if they had more water they might have grown in the hilled up section too, I will see next year. I believe that the hill of dirt still helped to keep the soil in the trench beneath moist which allowed the tubers to grow closer to the top of the original fill line.



Final harvest from two beds est ~ 50kg.

Most modern varieties of potatoes rarely flower and fruit, I have only seen one of mine do it once.

If you can get hold of some heirloom varieties (which are probably banned from WA ) they will flower and fruit and you can experiment with cross breeding them to get weird and wonderfull combinations.

See here fo more info: http://theextremegardener.com/?p=217

Harvested mine last night. Got a whole lot of nothing. Bummer.

I was forced to do my sweet potatoes that was as my wife decided to use the compost for other stuff. We shall see if it works that way. It is how I was told to do it in the first place.

UPDATE: so all the ones I grew in bags with earthing up method are out. I probably got about 1.5-2 x the amount I put in. However, I got a lot of very small guys, which, had they bulked, probably would have doubled my crop again.

I have one lot in a pot that I have not been hilling up on, I just gave them sufficient room to grow from the start. So we will see how they go. However, the got ravaged by a bug that deceptively looked like lady bugs, until I realised the bug was eating and not protecting the plant from something else!

Anyway, I am committed, since the first lot I did over a year ago in a pot were beautiful lush plants, that went all the way to flower, and produced a bumper crop.... Clearly I'm just doing something wrong now.

I feel my down fall is two fold:
1) when doing the earthing up technique I was not giving the plants much space in the bottom of bag. Since they did not grow up the stems like promised by the earthing up method, they had little room to expand.
2) keeping the plant healthy and alive through the "bulking" up phase. This is a combination of enough watering, keeping bag cool/out of sun, protecting from insects. Keeping the plants healthy right till the end is the main difference between my experiments this year and my first bumper crop. I read that when the plant is stress or photosynthesis is compromised, the bulking up can be grossly effected.

I will continue experimenting and providing updates at the end of each experiment on what I did and what yield I got.

I've got a new bag on the go now, and will concentrate on this one. Post again in another few months.

P.s. I neglected to do most this for the bags I just reported on...so don't take what I said I would do as what was actually done.

I have three large coffee bean sacks which I have been planting with potatoes, lots of nice greenery on the top but having watched many YouTube videos where people tear down a stack and only find one or two potatoes I am beginning to think there is more to this than just chucking a potatoe into a sack and covering it in dirt.

One plant just keeled over from the sun and I couldn't revive it. Couldn't have been getting enough water.

One of the plants is dying back a bit now but is being very stubborn and still has greenery on it, it threw out one little flower which I pulled off in the hopes that it would encourage it to keep growing. The whole family will be there watching as I tip the sack out,

Seed potatoes $3
Hessian Sack $2.50
Soil/compost $35
Sugar Cane Mulch $2
Water $0 (about the only thing that is free until the Qld gov can find a way to charge for rainwater)

I need to get more than one potatoe out of this, I am still being mocked for my inability to grow capsicums in this country!

I found that having the bottom of the sack in a plastic is good for catching rainwater and saving the patio from getting covered in dirt but the hessian rots in less than a week and it starts to smell bad, I guess it doesn't wick back up. I am now putting the sacks on a bed of gravel so that they are not sitting in water and they seem to be better off. I hope to get at least two uses out of the bags but if not I guess they will go to the worm farm. I have also put a 5cm layer of drainage gravel at the bottom of the sacks to also try and save them from rotting.

Each time I hilled the potatoes up I put a 5cm layer of the sugar cane mulch on top to stop the soil drying out, I just added fresh compost and soil on top. I will see if there are more or less potatoes growing in the mulch layer.

All I used for fertiliser was worm compost, dynamic lifter pellets and I watered once with some worm tea, other than that they have only had what was added to the commercial potting mixes I bought, each sack has about 80litres of added soil and I am hoping that I will be able to reuse the soil.

The hessian colours up quite nicely in the garden and doesn't look bad, the white woven bags look a bit industrial and from my experience they tend to disintergrate in the Queensland sun, I haven't tried any of the commerical bags.

Unfortunately with potatoes, it's not the lush green on top that decidedly the number of potatoes. In fact, it's probably more like a lawn, if you feed it high nitrogen it will look beautiful, but won't invest in roots. Hence not very durable. If you feed it with high potash fertilizer it might look ordinary on top, but BOY! will it grow good health roots.

Moral of story I think is more potash less nitrogen, but this is only what I've read/watched.

A 'Before' picture, hopefully it will be worth taking an 'After' picture!

Something is happening to my system. It is not working to allow me to add a photograph.

I think Dr luke is right about the potash, which you can get for free by just adding the white ash from a fire.

I also know that spuds like consistant moisture, could it be that the bags allow the soil to dry out too quick and this affcts tuber production?

I grow mine in wicking beds which keeps the soil moist and have been having reasonable success with 4 to 6 good sized spuds per seed spud, a good yeild is considered to be 8 to 10 spuds per oringinal seed potato, yet to get there but will keep trying.

I did put some wood ash into the mix but didn't want to put too much incase I make the soil too alkaline. The plant that was not doing so well got some watering from a bucket that had some wood ash in the bottom so I think I probably watered it with Lye, that probably didn't help it over much...

The hessian bags do dry out which I guess does allow air to get to the roots but I do water it every day and it is mulched on the top. The plant never shows signs of wilting so I do not think it is too stressed.

I only planted one seed potato in each bag, 4-6 back is no mean feat but that won't even feed half the family for one meal. I don't mind the occassional hessian bag in the garden as a bit of a talking point but I might just swap to wicking beds in that case.

I thought it was too good to be true! I envisaged being swamped with potatos from each sack! It does look a bit lumpy!

I think Simo is right about the water too. I find the bags fare less well than the large pot. I suspect this is mostly because the bags heats up in the sun and dry everything out. This can't help for tuber production either, since they can only bulk below a certain temp apparently.

I have put my latest experimental bag down the side of the house that is shaded most of the day.

Great, hopefully u'll have more luck than me.

Yep, all the videos I've seen put at least 3-4 seed potatoes in a bag.

I have one in full sun and one which gets mid morning to early afternoon sun and then is in shade.

I also put in some rotting branches at the bottom which I soaked in a bucket of rainwater for a few days. Sort of like a mini Hugelkultur bed. I will see if the branches retain much moisture when I dig it all out. I also used a lot of worm compost which should also hold some water because of all the organic material.

I am hoping that is is wetter and cooler in the middle.