[tippben]

I'm planting spuds in a raised bed 4' by 13'. I've covered it with black permeable mulch membrane, as I can then fit two rows in, as I won't need to earth up. Would I get away with watering with the hose, by putting it under the edge of the membrane between plants? I was going to do a row of plastic 3 litre bottles down the middle for feeding, and extra water, but it'll be difficult to stop them blowing away. Thoughts?

[michael brenock]

if the membrane is permeable then rain should be able to get through or sprinkling with a hose should suffice. However potatoes need to be earthed up as soon as tuberisation begins and if this is not done then a lot of the tubers will be very close to the surface and even with the membrane in place some greening will occur. Earthing up as it is referred to should be done when stalks are 6-8 inches high. The membrane will exclude weed growth but small holes have to be made to allow the stalks to grow through.
michael brenock horticultural advisor (retired)

[Ben Yezir]

You can top the membrane with straw, which is what I intend to do, then put some bird netting over the top to keep it in place. Better still, put the straw under the membrane, 3 inches or less should keep all the light out.

[tippben]

If the light exclusion will be the main problem, could I put a thick layer of newspapers/cardboard covered with grass clippings on top of the mypex? I could then dig the result into a bed next winter We've used every square inch of our garden, polytunnel, pond and eight raised beds, so we literally won't have any spare soil to earth up, and buying it would defeat the object of growing something as cheap as spuds (Orla by the way).

[Ben Yezir]

That would do it. However if your barrier is pretty lightproof, you won't need much else.

[tippben]

Haha! I'm getting some straw from a farmer. I'm going to cover the membrane with cardboard, then when I mow the communal grass outside, I can scatter straw first. Then it'll all be mulched up together and should compost better than straight grass clippings. I've put nematodes under the membrane to kill any slugs under there, and tried the bottles (every foot, between plants, using canes inside for stability), plus the hose- it seemed to drench the ground ok. It's my first time trying this no-dig method, so I'll post updates and photos on results, good or bad...

[michael brenock]

dear tippben the original query was very straightforward but it has become quite complicated and it is a challenge. Apart from the exclusion of light there is a need for the potato roots to have something to anchor on as well as feed.. The potato plant is simple in form but complicated in others. To grow potatoes merely to propagate the species can be grown without excluding light but for producing edible potatoes light must be excluded. Another means is by growing them in to tal darkness and give them a dosage of light every day.
michael brenock horticultural advisor (retired)

[tippben]

thanks Michael, but that leaves me a bit confused- it's a double dug deep bed with an extra 8" above ground as well, so a good 18" to 2' of decent improved soil. It had lots of compost and manure for legumes last year, and more manure this winter. Is that not enough growing media? I thought that with all the haulms growing through slits, the tubers would spread through the ground.

[michael brenock]

that sounds like a good basis for growing potatoes. i hope all goes well, let us know how you get on. it would be a very interesting and new approach to growing a very old crop.
michael brenock horticultural advisor (retired)