[Marijke Jones]

Dear fellow gardeners,

I want to grow potatoes and use potato bags for that. I saw you have many sizes but what is the best size and how many seed potatoes go in that preferable size?
Can I use compost or does it require other soil in the bag?

Your experienced advice is much appreciated.

Maria

[Grubbypaws]

I use Gardman grow it potato planters which are 31.5D x 31.5W x 55H centimetres which I think is 50L. I have also used the Haxnix planter which is 40L. Both have worked fine with 3 tubers (4 if small). The instructions say 3-5 seed potatoes but I would imagine that it would be hard to protect the chits if planting 5 

I use my garden compost with some Vitax  Organic Potato Fertiliser which I put around the tubers at planting time. The quality of the compost doesnt really seem to matter so if I havent enough well composted stuff I use less well composted and it doesnt seem to make much difference.

Once the hulmes are fairly sizeable I start using a low nitrogen liquid feed. It must be low nitrogen or you will just encourage leafy growth at the expense of potato yield.

The only thing to say about growing in containers is that they will need careful watering.

[Yorkie]

In addition to everything which Grubbypaws has noted, generally you put just a fairly shallow layer of compost in the planter to start with, and put the tubers in there and cover them over. Add more compost as the haulms (stems and leaves) grow through the existing compost layer, until you reach the top of the planter.

In this way, you're reproducing the 'earthing up' of traditional soil growing.

[Marijke Jones]

That is fantastic advice! Thank you 🙏

[Tenhens]

Grubbypaws reply about watering is sound advice , particularly with this year's weather.
I have been growing in bags for the last couple of years and get through a significant amount of water which I collect in one of those ibc cubes.
My bags came from JBA  and I would recommend them , worth paying that bit more.
The flavour of home grown potatoes and anything else far outweighs any shop bought produce and is well worth it.

[mumofstig]

I use potato buckets nowadays, for longevity, plus a bit more moisture retention.
These are 30L and I do as shown here
https://www.youtube.com/watch?v=UivlTItfs_M
I bought mine for 3 for £9.99 + Yodel delivery charge from here
https://www.gardenbargains.com/item-p-130002/heavy-duty-30-litre-pots--pack-of-3

[Grubbypaws]

In addition to everything which Grubbypaws has noted, generally you put just a fairly shallow layer of compost in the planter to start with, and put the tubers in there and cover them over. Add more compost as the haulms (stems and leaves) grow through the existing compost layer, until you reach the top of the planter.

In this way, you're reproducing the 'earthing up' of traditional soil growing.

I put 8" in the bottom and then gently bed them in and cover being careful with the chits. A few years ago I was going to then be out of the country so unable to 'earth up'. Fingers crossed I simply filled the containers to the top and mulched to prevent weeds growing. When I returned I had extremely healthy haulms and got a bumper crop. I have used this technique ever since saving hours of work.

[Tenhens]

Am I right in thinking that tomorite tomato feed is low in nitrogen?

[Grubbypaws]

Am I right in thinking that tomorite tomato feed is low in nitrogen?

I have always used Chempak low nitrogen food which I have just taken at face value (Low nitrogen). Checking their website today I see that it has a N:P:K ratio 12.5:25:25 which is a low nitrogen ratio but still quite a lot of nitrogen Tomorite has an N:P:K ratio of 4:3:8. Interestingly Chempaks specialised slow release potato feeder has a ratio of N:P:K - 4-6-12 +4MgO which surprises me as it has K value which I thought was for good fruit. I would have thought it would have had a higher phosphorus for root growth  I am going to have to do a bit more research here. I would love to know which the forum thinks is best for our container grown potatoes!

[Yorkie]

Potato fertiliser has a NPK ratio of about 4 - 2 - 8.