growing potatoes under membrane

[bluebellParticipant]

I have half a plot covered with weed membrane and intend to plant potatoes on some of it. Original idea was to punch holes through and insert potato, however it would make the membrane unusable and so I was wondering about planting in the ‘join’ between sheets. Any thoughts on issues with this? May be a bit more weeding but would at lease mean I was not throwing out 100 meters of membrane at the end of the year.

[charlesModerator]

Hi Bluebell. If this membrane is Mypex I recommend making holes with a blowtorch if possible to avoid loose threads polluting the soil. Then you can reuse the membrane but with some cardboard slotted into each hole to maintain darkness underneath. Or fold it to double up if covering a smaller area.

[Don FoleyParticipant]

Hi Bluebell,

Why not just weed the area your going to sow the spuds in then cover with compost per Charles’s recommendations and plant the spuds through that. Much simpler and less time consuming.

Don.

[bluebellParticipant]

Hi Don
If I had that much manure available I would but the plot is approx. 30 feet by 40 feet and full of weeds, having been untended for 3 years. I simply don’t have that volume of compost or manure available. I am also pushed for time as sods law says the plot became available at a time when lots of other things are going on in my life. So the potatoes are a low work option to get the ground cleared for more intensive planting next year.

[JohnParticipant]

Hi Charles and Bluebell

I am in a similar situation with what was a very weedy plot which I have covered with about 3-5cm of muck and then covered with mypex or plastic sheet.

My question is about whether the mypex will be sufficient to stop greening of the potatoes as it will not be practical to earth up.

I plan to burn holes at 60cm centres so the sheets can be used for potatoes, brassicas, courgettes, squash etc. I think the 60cm spacing, giving 2 rows across a 1.2m ‘raised’ bed, is quite adaptable and could be used many times, particularly if my rampant bindweed is slow to clear!

I have lots of photos on my blog

[charlesModerator]

Sounds good John.
Mypex does let a little light through and any potatoes growing to the surface will slowly green but it should not be many and I think you could trim that off before cooking. Its worth it for having a lot less bindweed, let us know how it works.

[JohnParticipant]

Thank you Charles.

[Don FoleyParticipant]

Hi John,
I think the 60cm spacing is rather generous.
I use 30cm each way for early potatoes and 45cm each way for cabbages.
I get very good returns using these figures.
I would just be thinking your wasting a lot of ground.
Don

[Don FoleyParticipant]

Hi again,
I meant to add in my last post that I never use Mypex because it is so expensive.
I found using 1200 grade damp proof course very effective and vastly cheaper.
This is a heavy duty plastic sheeting and it is great for clearing weeds and heating up the soil.
Don.

[RhysParticipant]

Bluebell

Like Don, I plant potatoes at rather higher densities than you’re suggesting.

I go: 30cm within row and 40cm between rows for 2nd earlies; 40cm within row and 50cm between rows for main crop. My ‘rows’ go across a 1.5m wide bed, so they have either 4 or 5 tubers per row.

For both I get around 50lb for 3 square metres sown. I’ve had higher for main crop, but not consistently to date. You may not get that much on a new plot…..

By doing this you get a very dense foliage which pretty much eliminates weeds.

I also ‘hill up’ using a combination of grass clippings, comfrey leaves and compost/manure, which helps to create a great tilth within 12 months of sowing your potatoes.

[JohnParticipant]

Hi Don and Rhys

My question was specifically about weed membrane, what my allotment shop calls mypex and which is 105g/m2. I think it is a copy of the actual brand ‘Mypex’.

Don
Perhaps you missed my comment that the 60cm spacing was for ADAPTABILITY, for widely spaced crops such as brassicas (I am thinking about sprouts, PSB), courgettes, squash etc., not just potatoes and not specifically early potatoes or cabbages. I hadn’t intended the spacing to be the optimum for every crop. The RHS recommends 37x75cm spacing for maincrop, giving 2775cm2/plant. My planned spacing of 3600cm2/plant is generous for potatoes, but the adaptability for other crops is my aim. I am lucky in having a new second plot so I wonder if a generous spacing is not a bad thing until the soil fertility builds up. I know that Charles is able to grow very intensively because he uses far more compost than I have, hence my thinking about growing extensively.

For my weed membrane the allotment shop charges £0.50/m2 and much less if I buy a full roll. I have googled 1200grade dpc and have not found anything ‘vastly cheaper’, and it is generally more expensive unless buying 100m2 or so. It would be useful to have a link to your cheaper source. I think that Charles, in a previous thread, has recommended using a much thinner and cheaper plastic in answer to a similar comment about 1200grade dpc. I agree that thick plastic is great for suppressing weeds, but I wonder if the permeability of mypex is better for growing crops, particularly on a concave raised bed or slope where we might get sheet run-off with impermeable plastic.

Rhys
I don’t think that hilling up is viable when planting under mypex or plastic sheeting and the hope is that it is the membrane that will eliminate the weeds.

[Don FoleyParticipant]

Hi John,

I get my dpc from a local hardware shop and it costs 40 euro for 100 sqm.
On the other hand the cheapest I can get Mypex is 48 euro for 50 sqm more than twice the price of the dpc.
I think you will agree the dpc is vastly cheaper than Mypex, in Ireland anyway.

Don.

[JohnParticipant]

Hi Don

Ah, there’s the rub, the bad luck of the Irish!

[Don FoleyParticipant]

Lol

[Author]

Posts