Growing potatoes in sacks saves lots of space and doesn’t require a garden, - you can even grow on a balcony or small concreted yard.
How to plant potatoes in Gro-sacks
- At the appropriate planting time set five tubers on top of a 15-20cm (6-8in) layer of good quality compost in each Potato Growing Sack
- Cover the tubers with a further 10cm (4in) layer of compost and fertiliser
- As the plants grow and shoots emerge above the surface, add more compost to the potato growing sacks to cover the shoots
- Repeat as needed until the compost is about 5cm (2in) below the top of the bag
- Always keep the compost moist but don't saturate it as this might cause the tubers to rot
How to feed and water potatoes in Gro-sacks
Potatoes need plenty of moisture, particularly round about flowering time which is when the tubers start to form. An occasional heavy watering is better than little and often as this does not get down far enough and encourages shallow rooting.
An application of a high potash fertiliser at the rate suggested on the pack will increase yields, avoid fertilisers high in nitrogen as these will delay maturity of the crop.
How to harvest and store potatoes in Gro-sacks
First Earlies: Best harvested in small quantities and eaten straightaway when fresh in June and July, harvest when flowers are fully mature and open.
Maincrop varieties: Can be lifted from September onwards and stored as long as the tubers are lifted in dry conditions or are properly. Store in a hessian sack in a cool, dark, frost-free area.
Harvest when leaves and stems have all yellowed, remove yellow stems and harvest potatoes a week later.
The 7 Secrets to Growing Success with the Marshalls Potato Growing Sacks
As the original developers of the Gro-Sack, Marshalls experience in achieving the best yields is unmatched. Follow these 7 points to grow the best Gro-Sack potatoes.
1. Chitting Potatoes – Chit tubers (to produce sturdy shoots) in a cool light place before planting to encourage quicker establishment and growth.
2. When to plant potatoes in growing bags – Start your grow sacks in greenhouse or conservatory from as early as February and move outside when all risk of frost is past.
3. Where to grow potatoes – All potatoes do best grown in a light, warm sunny spot.
4. Soil / Compost – use a good proprietary compost or an equal mix of compost and soil and place a layer 4-6 inches in the bottom. Place potatoes on compost and cover with a further 4-6 inches of compost.
5. Earthing Up Potatoes – Potatoes grow from the stem beneath the surface. So keep covering the foliage with more compost as it grows until the sacks are full to within 4 inches of the top.
6. Feeding and Irrigation – This really is the big the secret. Mix potato fertiliser or a good general purpose fertiliser such as Growmore with the compost during planting and earthing up. Keep compost consistently moist (but not over wet) and you will reap dividends for your crop.
7. Potato Pest Control – Finally, Potato Blight can be a major problem from July with later yielding crops. Help fight this fungal disease with ‘Fruit and Vegetable Disease Control’, a traditional, protective fungicide.