Grow Your Own Magazine

Hi I have 12 seed potatoes that didn't fit in the bed so have bought some bags of compost (not got any made of my own yet) to put them in.

The bags are 25 litres. How many earlies will I get in each bag and how do I do it? where do I store them? How much water do they need? Do they need drainage holes?How do I know when they are ready?

Jamie Oliver was doing similar on the tv the other night but by the time I had run in to see it I'd missed it!

Thanks, janeyo

I'm not a Jamie Oliver fan by any stretch of the imagination, but then he's no gardener

I do, however, grow potatoes in bags and pots, so I hope I can help.

In my book, 25 litres of compost should take 2 earlies, roughly. I grow three earlies in about 35 litres. Feel free to experiment, though. Try one with 2 and another with 3. See how your crop compares.

Do you mean you want to grow potatoes in the bags you've bought? I assume you do.

Thing is, normally, you start with an empty bag - do you have somewhere you can decant the compost or is there another bag or pot you can use?

Anyway, starting with an empty bag, this is what I do:

Make several holes - say eight, about hole-punch size - in the bottom of the bag, then throw in about an inch layer of something bulky like broken up polystyrene chunks or old broken pots. This layers helps keep the holes open under the weight of the compost. The potatoes like moist soil, but they don't want to be kept wet. You could try one bag without the drainage layer and see how it compares.

Fold the sides of the bag down outwards, as if you're turning it inside out, reducing the height of the bag by a third. This makes things more manageable and you can just roll the sides back up as you add more compost.

Now add about four inches of compost. Place your tubers in/ on top of this - if you have shoots on your tubers, make sure they are facing upwards. Now carefully add another three or four inches of compost. The tubers should be well covered.

Water the bag, especially if the compost is dry, and then leave well alone.

In a couple of weeks, roughly, the first shoots should push through the soil. Once they are all through (one per tuber) and you can see the leaves opening, add another lot of compost. You can cover these initial leaves or leave the tops showing, they grow so quickly it doesn't seem to matter. The key is to keep the stems covered as they grow as the tubers form on long shoots outwards from the stem.

After a couple of top ups, you should reach the top of the bag. Don't fill it right to the top - you will make it more unstable, and you need to have plenty of room to water.

As the foliage grows, keep watering the bags. Remember moist, but not constantly wet. In reality, it is hard to over-water compost in containers like this, so you can be generous. You can feed the potatoes too, with some liquid feed - choose something appropriate for vegetables, obviously.

In about 90-100 days from planting (all being well) cross your fingers, get your hand in the sack and see what you can find. The size of tubers will vary within the sack, so check to see if any of them are usable (depends whether you like "hens egg" or bigger, it's really up to you)

To harvest, you can tip the whole bag out, or just grab a few tubers and leave the rest alone to grow some more. If they have reached a good size and you want to keep them for a couple of weeks - remembering that earlies don't store fantastically - pull out the leaves and stem and leave the potatoes in the compost. If the plants are healthy, they will come to no harm. Stop watering, obviously.

So there, I think that's pretty much what I do.

Hope it's clear.