Growing Potatoes In Marshalls Potato Gro Sacks

17 September 2009 | Posted in Gardening by The Marshalls Family

I filled the gro sack with regular peat based compost to about 6 inches high. In this compost I mixed in some Growmore.

I put the 5 chitted potatoes in the bag as the number 5 would appear on a dice, one in each corner (not too close to the edge) and one in the middle.

I covered the tubers and chits with compost and added a little more Growmore watered well and placed in a sunny spot in the garden.

Each night I would water the potatoes if the compost looked dry.

As the shoots grew through the compost I would add another layer of compost with some more Growmore mixed in. When the compost was about 6 inches from the top of the bag I stopped adding compost to allow plenty of room to water the bag.

Potato leaves get quite big so the bags were spaced out to give them room. Giving them room also reduces the chance of blight as the tops have plenty of air flow.

I continued to water the compost well, not the leaves as this can encourage blight, and gave an occasional liquid feed if there was any left in my can after watering my flowering tubs.

I sprayed with Dithane twice when the weather became humid for protection and the fact that these potato sacks were going to be used on our stand at Hampton Court and the plant had to look good!

James pot grow sack

I emptied one of the sacks last week when the tops had completely died down and counted 62 potatoes weighing in at 3.5kg (7lb 12oz)!

I must emphasise the importance of feeding, watering regularly, protecting from blight and waiting long enough for the potatoes to grow before you harvest them.

Potato Grow Sacks work extremely well, as long as they are well fed and watered regularly and given plenty of sunshine.

Did you grow potatoes in grow sacks this year? Let us know how your growing went by commenting below.

 View our Potato Growing Bag Guide and Tips here!


18 September 2009 - niki Wrote:

I bought 3 sack to grow my potatos in, I did everything you have said you did to yours. I too had lovely large leaves and was looking forward to a large crop but was I in for a disapointment! I had barley a 11/2 of potatoes in each sack. My father-in-law had the same results as myself. We both have grown potatoes before and grow successfully lots of vegetables with out problems. We were both really disapointed with the sacks

21 September 2009 - James Oakey Wrote:

I am sorry to hear you had poor results. I had three sacks all of which produced great crops. The potatoes were in fact a customer return to our warehouse so there was obviously no problem with the seed.

If you could answer the questions below I will try my best to identify what went wrong:

  • What fertiliser did you use?
  • How often did you apply?
  • What compost did you use?
  • Where were they located?
  • Did you spray for blight?
  • When did you plant the potatoes?
  • When did you harvest?
  • Had the potatoes flowered before you harvested?
  • What varieties did you grow?


26 September 2009 - claire Wrote:

I used the marshalls potato sacks with the early new potatoes. The instructions said to fill the sack to within 6 inches of the top - should I have done as you have said James with these varieties as well and start nearer the bottom of the sack. We didnt have a huge crop (but thats because I didnt turn the instruction leaflet over to where it said when the shoots appear cover them!!) perhaps just a couple of dozen small potatoes in each bag - but they were delicious. I am a budding vegetable gardner so learning anything I can from people who know..... thank you

26 September 2009 - Mark Wrote:

We had 3 sacks with Charlotte potatos and did pretty much as advised on the instructions. There were a few times where I forgot to water the sacks in the evening and I dont like to use chemicals so I didnt spray for blight which isnt usually a problem for me thankfully and I used my own compost instead of artificial fertilisers. Two out of the 3 sacks did pretty well with 20- 30 decent spuds in each. One sack was harvested a bit too early and did less well with about a dozen smaller spuds only. Overall, I thought they did pretty well, certainly well enough for me to buy another 3 sacks for next year, to give 6 in all. What I did find is that they took longer than I was expecting to develop a decent crop of spuds, hence the first bag turned out too early. I also think that watering was key to success so had I not forgotten a few times then I might have done even better.

29 January 2010 - Harry Wrote:

This may be a daft question, but what do you do with the spent compost? I am assuming it is not used again for growing the potatoes the following season.

08 February 2010 - Ian Coghlan Wrote:

I have grown potatoes for in bags for years as our garden is prone to eelworm. The secret is to pick a spud that is good in sacks, charlotte and nicola give good results. Water well, feed well (I use a high postash feed) and don't harvest too early. As to soiling up. Think like you are growing them in the garden. Plant in trenches, earthing up as the stems grow until the stems are good and strong. In sacks start with about 6 inches of soil at the bottom and then carry on covering the stems as they appear until you are couple of inches from the top. I use the leftover compost for containers of bulbs and then it is spread on the garden when they are over.

19 February 2010 - dennis wallace Wrote:

I tried the Gro Sacks for the first time last year but did not get a high yield. I had 3-4 sacks and put in as instructed and built them up. Watered well with feed and left out till the due dates. I got about 12 potatoes from each so not bad for a first time but not great either. This year I aim to put a little more Growmore in and also I have bought Potato fertiliser. Any other tips would be helpful.?? I have a plastic covered Greenhouse Could I put the bags in there at the end of February do you think??


Hi Dennis, sorry to hear that you didnt have much success we have some tips in this growing guide - at the bottom. Take a look and let me know if you did anything different, I grew potatoes in our growing bags last year and had a fantastic crop. I would definately put the 1st and 2nd earlies in the greenhouse to start them off, you should bring your cropping period forward by around a week to ten days by doing this.

21 February 2010 - Jean Wrote:

I'm considering growing potatoes in sack for the first time this year, my concern is does the whole sack have to be harvested at once? If so and I'm fortunate enough to get a decent crop, I'm worried about how to keep the potatoes so that they do not spoil before I get around to eating them all.


Hi Jean, no you dont have to harvest the whole sack at once. You can simply root around in the compost and take a few at a time, leaving the other potatoes to grow a little more and keep nice and fresh.

21 February 2010 - Lesley Perschky Wrote:

We tried some potatoes last year but had no luck at all. They all died off, mainly due to a slug invasion! Is their any way that we can prevent this happening again and what is an easy type of potato to grow?

04 March 2010 - Dennis Wallace Wrote:

It was my first year and I hope I have learnt from those mistakes.I am trying first earlies and second earlies in the gro bags you sent me.I have applied growmore and potato fertiliser to the bags before I put the chitted potatoes in them.I am going to put these in a civered plastic greenhouse . Would this be ok for them?? Then as it gets warmer and frost free I can add more compost /fertiliser as they grow etc. I did this last year but I think we had to much rain!! Otherwise perhaps not enough fertiliser last year? Thanks Dennis

10 March 2010 - Ted Sofocli Wrote:

I have just received my potatoe grow bags, I understand that chitting helps to speed up growing and that planting should begin when th growing stems are about 20mm long, is this right, next, when is the earliest that planting can take place, I do not have a greenhouse/cold frame, but a sheltered south facing wall that gets all day sun. I live in NW London.

03 April 2010 - Karen G Wrote:

I had 3 sacks and an old fashioned rubbish bin last for my first attempt at growing my own potatos and the results were fantastic! I had a great crop and the flavours were wonderful. I grew Charlottes, Vivaldi, Swift and Rocket. The biggest disappointment was when my crop ran out and I had to resort to buying from the supermarket again! This year I'm growing in 9 bags, the bin and 2 car tyres and I hope to start harvesting Charlottes in 10 weeks!

03 April 2010 - Martin (Spud) Moseling Wrote:

Last season was my first for spuds in bags and I had loads of top growth but a bit disappointing in the under parts. I used tomato feed so perhaps that was the wrong NPK mix. The Charlotte had great taste. This year I have bought another set of bags and will try Maxine. If I don't have good results I'm going to bury my brother-in-law's body parts in the bags as I'm fed up with him saying "You can buy them cheaper in the supermarket". Don't give up - every growing year is different.

06 April 2010 - Phil Wrote:

We're expecting the delivery of our starter kit any day now however I'm lost as to what type of compost we should be using. It's our first attempt at vegetable/potato growing via this method (via any method in fact) and there are so many types and stage composts thus I don't want to end up purchasing the wrong one....i.e peat based, not peat based etc etc. Not sure if it's noted anywhere but whilst I'm at it can anyone tell me roughly how many litres of compost I will end up needing per bag...Any advice please?

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