[BumbleJo]

Hi folks, having overdone it on the seed spud thing once again and filled my raised beds was planning to use the rest in sacks but wondered how many to use as have seen everything recommended from 1 to 5(a layer of 3 then a layer of two).  I assume the more seed spuds the smaller the size of the spuds when harvested but more of them? Also as I have 1 of this and 2 of that left does it cause any problems using different varieties in the same 40 litre sack? Thanks!

[Trikidiki]

Spot on, the more or bigger the tubers you put in the smaller the ones you are likely to take out. I generally put three average or two large tubers in the readily available bags. I think the surface area of the bag is more the restriction than the total volume so unless your 40 litre sack are very wide I wouldn't expect to fill the bag before harvesting. Treat them like a catch crop of small sweet spuds.

Mixing the varieties would only matter if one grows much larger than the other. I would keep them to the same variety as much as you can but wouldn't lose any sleep over it after all it is pretty much a bonus crop for you.

Keep them in a greenhouse if you can for as long as you can or pamper them with polythene or fleece to try and encourage a crop earlier than yours in the bed. If the internal surface of the bag is black, turn them inside out so they warm up quicker (or use clear bags   , no don't the spuds will go green if near the edge).

[lettice]

Been growing first and second earlies for years in 30 litre pots and larger potato bags.
Put 3 in the pots and four in the bags and they are always bulging by harvest time.
Do place the pots and bags on soil allowing the roots to go into the soil and bring up more nutrients.
Did as a test once try them on a concrete surface and the crop was not as good and they dried out much more.
Just use a mix of garden soil and multipurpose compost and add some potato fertiliser.
I also add a few lengths of seaweed to mine, but living near the sea, its easy to come by.

I would not mix varieties, as they do grow at differing times, albeit a few weeks, but you will be unsure for next time which variety did well. You could always use a smaller pot for just one or two, say 20 litre.

There has been some talk recently of layering the potatoes in bags and pots, not tried that but may be worth watching if it works.

Grow mine much the same really as this guy does, just take his large pot as a large potato bag;

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Here is the layering technique

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[Tenhens]

Have watched the first video, wonder why he doesn't tip the mpc into the bucket and then check for lumps, would save time.   Would it make any difference if white buckets were used, have a 'stock' of 20 litre white ones.   Interesting to see the potato's growing in what appear to be flower pots. 

[Trikidiki]

As long as they're opaque you can use pink if you like.

[mumofstig]

The plastic deteriorates quicker than black ones do - and the soil will get warmer. Other than that I don't think there's any difference. (my big tubs are white btw  )

[BumbleJo]

Thanks for all the info folks, 5 bags made up just got to wait and see now!