[Odin]

Has anyone tried growing veg in the large one tonne builders bags ? I was informed that there is a record for the heaviest yield of spuds grown in these bags by continually earthing up the potato plant. Definately going to have a go.

[cloddopper]

If you do grow in the bag it might be an idea to make a four sided enclosure out of pallets , and have a floor under the bag so excess water can drain out.
   
Planting a well chitted spud about every square foot should see you off to a good start. Don't over water or over fertilize or all you get is seven foot long tops like I did. 

 When you set the initial bed use 6 inches of bed with a bucket to the whole layer of old seasoned manure. Plant the spud at 3 inches from the bottom . When the tops come up 5 inches , top up three inches of new bed , carry on in this manner till you reach the top.

 If you can wrap some black plastic round the outside of the pallet wall this will bring the contents up a few degrees .. I think my USA pals say 65 oF in the ground  is a good temp to have when growing spuds in the builder bags.

If you don't use pallets to contain the bag , the bag tends to slump like a not very tall 26 stone couch potato and will often only be just over 2 feet tall.


 When I did my spuds in the green house in bags ii made the fatal mistake of using too much manure & giving them too much liquid tomato feed too often I also had them on an auto drip watering system.

Not only did I as previously said , get 7 foot ling tops the actual spud size was about the size of bantam eggs , out of five King Edward spuds I only got 12 spuds .

 The outdoor bags fared better but again over watered over fed and fed too often , but not on the auto watering , they had three foot long tops & gave me about a stone of spuds out of the four 2 x2 x2 foot bags .

[Bramblecot]

OH grows his pumpkins in a hideous creation made from a builders bag.  4 stakes through the corner loops and a supporting rail around the top .  Keeps him out of mischief

[cloddopper]

Is that growing big pumpkins using a wet straw bed ,  fed on liquid manure etc. & taking the productive runners out to grow on a straw mattress adjacent to the root holding bag ?

[Spinningfishwife]

I used to grow the Halloween pumpkins in a builder's bag when I had the allotment. I supported the bag using four stakes and a top frame as described above and then used it as a temporary compost heap at the end of the summer. In the spring I topped it off with a six inch layer of rotted manure and six inches of straw then planted two young pumpkin plants into diagonally opposite corners. They grew like wildfire, I didn't feed them anything extra but kept them well watered. You do need to keep up the watering in a builder's bag, they dry out very easily.

It would no doubt work perfectly well for spuds except I'd skip the manure. Maybe plant them though a layer of wetted cardboard? I used to plant spuds through cardboard in my raised beds and it meant I didn't have to earth them up. I'd put a layer of straw over them to keep them warm in the colder spells though.


ETA: At the end of the pumpkin growing season you'd be left with a very useful bag of compost to spread elsewhere.

[Lesley Silvester]

I've grown pumpkins in compost bins filled with semi-rotted manure and it worked very well. They certainly grew huge.

[Bramblecot]

Clodhopper, Nothing so technical.  Just fill up the bags with muck-outs from the chicken and sheep.  Earth and old compost on top and away they go