as long as the tubers have at least 3" around each one so they have room to grow that will work. they will need plenty of water once they get into active growth. add slow release fertilizer granules to the compost too.

What great advice! Thankyou SBG. I'll make sure to plant as you advise. I'm not sure though what slow release fertilizer granules are. If I buy some what do I look for?

Slow release fertiliser granules are generally a 'balanced' fertiliser in little chunks that melt a little each time they are watered making them ideal for steady plant nutrition in a container. You'll find them for sale in Wilkinson, garden centres & a lot of the major £shops & supermarkets that do gardening stuff in Spring.
It's a slightly too large topic for a quick post but 'balanced' refers to the N-P-K rating that's printed on all fertiliser packaging. N=nitrogen, P=phosphorous & K=potassium, the main nutrients required for healthy plant growth. So a completely balanced N-P-K would be a ratio of 1-1-1 or thereabouts while a higher nitrogen content would be 2-1-1. It's a really good thing to read up on even if only to get the basics like which fertiliser to use when & for what reason.
Hope that helps☺

as Darren says they are a small pellet about 2mm in diameter that slowly dissolve and leach out of the casing. they are often taken for snail eggs when people buy plants. they come in a range of colours too. I've used Wilkos own as well as branded ones like miraclegrow. they are pretty balanced for general purpose growing of plants.

Thankyou Darren. I'll have a look when I go shopping. I usually just put chicken manure around plants at this time of year. Probably not good for a lot of plants. Your explanation was very informative.

Thankyou too SBG. I'll have a look at Wilco.