• Planting potatoes (and other vegetables) in pots and bags is a useful method of growing since it’s very flexible and suitable for early harvesting varieties or growing for exhibition.
• The bag or pot method is ideal for growing on patios and it’s also a good way of maximising yield in a small space. You do not need an allotment or large garden to enjoy the thrill of growing!
• By starting the bags under glass, the bags can be gradually moved to a sunny position by day as the Spring weather arrives. (Be careful to avoid frost, remembering that the temperatures given on the weather forecasts are usually for cities and rural locations may be colder!)
• The drawbacks include the large amount of water required, which for main crops is eight times those planted in soil. The constant need for watering (daily in dry summer periods) and higher levels of liquid feed must be kept in mind.
• Final yields for the average gardener can be disappointing if comparing to the claims of the bag manufactures. Luckily, there are some easy ways of making this method a bit more successful!
Let's Get Started...
Firstly, there are large plastic pots or strong purpose built bags. Pots are fine and can be any size e.g. an old retail flower container seen in supermarkets to any size you can find. However, plastic warms up quicker and may need even more watering. The bigger the pot the more seed tubers that can be accommodated. Always check for good drainage. The bags are usually purpose made and come in various sizes.
Fill two thirds full. The common advice is to fill half way and then top up. The theory is that when the plant appears you can keep covering it up and obtain more yield. This theory is good for those who have plenty of time but in practice it can be a bit impractical! This is because the extra yield benefit will only be realised if you do this on the day the leaves appear. Covering large sets of leaves will not increase yield, but may help with preventing greening of tubers and plant stability.
Compress the soil or substrate. This helps to retain water. Place the bag where drainage is assured.
The growing material used should be rich in organic matter to save water. Grow bag mixture is good but expensive. Soil may also be used. Add a potato fertilizer and mix in before filling the bag. Plant early varieties about four inches (10cms) apart and set them at least 4 inches (10cms) deep. Second early and main-crops - or simply if you want larger tubers from the plant – should be about six inches deep (15cms) and allow 8 inches apart (20cm) between seed tubers. When leaves appear add more compost to reach the top of the bag.
Remember to use seed tubers with as many eyes open as possible as we want to see as many stems as possible!
For best results I recommend using pots and bags for growing early varieties. If planted in February, you will be eating fresh potatoes in May. Allow 14 weeks for the earliest planting but those in April will be ready in 12 weeks.
The best early varieties for pots and bags are Duke of York Accent, Swift, and Winston.
Once the plant is well established, apply to the base a high potash tomato feed. Do this three times per week.
Hopefully this will help you on your way to potato growing glory!