Growing potatoes in containers
The container
- At least 20-30cm deep
- Minimum 30cm diameter
- Sturdy
- Drainage holes in the bottom
The growing medium
- Good quality potting compost – either purchased or home made. If using a large container, a loam, or green-waste compost, based material would be preferable. Although it is heavier than a loam free mix, it will make watering easier.
- Fertile garden soil, enriched with garden compost, well-rotted manure, or an organic fertiliser such as chicken manure pellets.
The potatoes
Some people advocate the use of early varieties, as they are quicker to grow and do not produce such a bulk of foliage. Others use maincrop varieties successfully. It is probably advisable to use a variety that does not produce very large tubers.
For later plantings, for a Christmas crop, choose a blight resistant variety if this disease is a problem in your area.
Timing
If you can protect the container from frost, and start it off under cover early in the season, planting can start as early as February, and finish as late as July.
Planting
The number of tubers you can plant in a container will depend on the diameter of the pot, and the vigour of the variety. Try five in a dustbin sized container, three in a 40 cm pot, one in a 25 cm diameter container.
- Put a layer, 5-10cm deep, of ‘crocks’ in the base of the pot to ensure good drainage. Use chunky bits of polystyrene packaging if you don’t have a supply of broken pots or coarse gravel.
- Add 4-10cm of growing medium (depending on the depth of the container). Place the tubers on this, equally spaced around the edge of the container. Cover with 10-20cm of growing medium. As the potato shoots grow, add more growing medium. Continue this “earthing up” until the growing medium is 4-5cm below the rim of the container.
Watering
This can be the most difficult aspect of growing potatoes in containers, especially where there are several plants in a large container. Both over and under watering are possible pitfalls. A consistent water supply is essential, especially when the plants are flowering and tubers are forming. You may need to water twice a day in the height of summer.
Feeding
There may be no need to feed the plants if the growing media was sufficiently fertile. Otherwise use an organic liquid feed to such as comfrey liquid in the summer. A foliar feed with seaweed extract every fortnight might also be beneficial.
Source: Garden Organic – Factsheet About Growing Potatoes in Containers
