seed potatoes in a grow bag

I have found that growing potatoes above ground in large sacks can be very successful and I’ll describe the way I grow my potatoes in this article. Hopefully this will be of use to some allotment holders out there.

First, I always use Clover compost. I have never had any problems with it, whether growing seeds or plants. Now that I am using a no dig method on the allotment, I’m using more compost to make up the beds and with Clover, everything grows as it should. A top class compost which is used by a lot of professional nurseries in the UK.

You’ll need to buy some sacks to plant your potatoes in. I prefer the large heavy duty polypropylene grow bags which can be bought on Ebay. Search for “potato grow bags” and get the 19″ ones which hold around ninety litres. Note: Don’t be put off by the cost of this method. A grow bag will cost around £4 and the compost will cost around £5, but, the bags will last for years and you can re-use the spent compost to make beds for peas and beans, the following season. The fact is that this method is foolproof and you will get some fantastic potatoes.

As to the type of potatoes to grow, I always grow early “new” type potatoes for salads, boiling and cooking “au gratin”. I tend not to bother much with late potatoes (for chipping, baking or roasting), but, having said that, I will probably try some late’s this year as I fancy growing a few Maris Piper’s or King Edward’s. Growing these in the ground is always problematic as you are practically guaranteed slug damage and/or blight. Growing in sacks may prove more successful.

So, you have your seed potatoes, your grow bags and your compost. Here’s what you do…

First, strim the ground to get rid of the weeds, or go over the ground with a hoe. Place your sack on the level ground…

ninety litre potato grow bag

A ninety litre potato grow bag

Next place around ten litres of compost on the bottom of the sack…

potato grow bag polypropylene

the bag has 10 litres of compost ready for planting

We now place five seed potatoes onto the compost. One in each corner and one in the middle. NOTE: If you want to chit your potatoes first then that’s OK, but you don’t need to do this to get good growth (in my experience). Chitting your seed potatoes just involves leaving them until they start to sprout. If you have ever bought a large bag of potatoes and the last ones have been “growing”, then this is what we call “chitting”.

seed potatoes in a grow bag

Adding your seed potatoes to the grow bag

Now, you want to cover the seed potatoes with about fifteen to twenty litres of compost and water in…

potatoes planted in a grow bag on the allotment

Potatoes planted into the grow bag and watered in

We now have to wait for the potatoes to grow. The stalks (or sprouts) will push through the compost as they grow. Keep the growth covered by adding more compost. Frost will kill the potatoes if the growth is left exposed, so cover with a good layer of compost each time the growth breaks the surface (about 10 litres of compost each time). I eventually use around seventy five litres of compost per bag before letting the leaves grow on.

Potatoes need a lot of water to grow, so make sure you water regularly throughout the season.

Potatoes can be harvested when the flowers have died off. You can root around in these bags and pick a few potatoes at a time leaving the rest to grow on. Also, if you leave potatoes in the bags till the following season, you can use these as your seed potatoes to start new bags off. If the potatoes start “sprouting” they’re ready to plant out, but do throw away all the very small ones as they need to be a reasonable size to grow successfully.

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