Growing potatoes – along with tomatoes, potatoes are probably one of the first grow your own crops that people experiment with.
Perhaps appropriately, both potatoes and tomatoes originate from the Americas and are members of the same family – Solanum.
Wild potatoes can be found growing from the southern states of the USA down to Chile in South America. They were one of the earliest crops domesticated in South America, around 7000 years ago.
With many people having limited space for growing their own fruit and vegetables, you may wonder if it’s worthwhile growing potatoes in your garden. Generally speaking, potatoes are not expensive to buy; until you want early potatoes or organically grown potatoes or a heritage variety that is.
So if you have limited space, or limited time, why not choose a variety of potato that your family likes to eat and which is more difficult to find in the shops or farmers market or more expensive to purchase.
What are Seed potatoes?
Seed potatoes are not seeds such as you would buy in a seed packet. Potatoes are grown vegetatively, which means the seed potato is a piece of potato rather than a seed from a pollinated flower.
Because of this method of propagation, any diseases that were in the potato crop the previous year will be carried within the seed potato. Which is why it is very important to use certified disease free seed potatoes and not leftovers from your weekly supermarket shop.
However, these seed potatoes should be freshly bought each year, as once they are in the ground they may contract soil-borne diseases which would be carried over to subsequent year.
You should get your Seed Potato order in early (November prior to planting) to ensure you get your favourite varieties. But garden centres and online seed merchants will still have seed potatoes available in February, so don’t worry if you’ve only just decided you’d like to grow potatoes.
How many seed potatoes do you need?
On average, 1 lb. of seed potatoes should yield about 10 lb. of potatoes. One lb. is about 5 – 8 tubers.
Chitting potatoes: which means? Chitting is a method of giving the potatoes a head start before you plant them; particularly useful for early varieties. Standing the seed potatoes in egg boxes helps to keep the chits or shoots safe from being knocked off.
Keep the tubers frost free, and in a light airy place to encourage strong growth of the shots. Wait for the shoots to appear, which could take up to four weeks for them to be ground ready.
Chitting potato tubers is not essential, so if you don’t have room, don’t worry too much. Earlies benefit more than main crop potatoes as the idea is to get them grown and harvested as soon as possible.
One potato, two potato
It is possible to cut the seed potato tubers into pieces, as long as the pieces have at least one eye each. An “eye” is a bud that grows into the new potato plant.
You can plant whole potatoes or pieces with multiple eyes, but generally speaking, the more eyes per piece more, but smaller potatoes. Whilst one or two eyes per piece fewer but larger harvested potatoes.
If you decide to cut your seed potatoes into pieces, cut them about 2 days before you plan to plant them. This allows the pieces to callus over the cut edge, which helps to prevent rotting and soil borne diseases.
Growing Potatoes in potato sacks
For details on this technique, check out our blog post “Growing New Potatoes for Christmas dinner“. The same method applies whether you’re growing new potatoes or main crop potatoes.
It can be fun to get some seed potatoes of Swift, one of the earliest early potato varieties, and start them off in January in a potato grow sack in your greenhouse. You could have your crop of first earlies almost before you’ve planted any outdoors. Starting off growing potatoes in the warmth of a greenhouse and then transferring the bags to stand outside should give you extra early early potatoes!
A thought to bear in mind for this year, 2016 – if you have heavy clay soil, it may still be very wet when your chitted potatoes are ready for planting. Why not try planting some of your potato tubers in potato grow sacks as well as in the ground? This way, you’re hedging your bets, so that if the wet conditions lead to rotting due to poor drainage, you’ll still have a crop of potatoes. This may be even more important to you if you’re growing heritage potatoes.
Growing potatoes in rows
A traditional cultivation method and still useful where you have the room. See also “Grow Your Own Vegetables in Rows” blog on explanations of some methods for growing your own vegetables.
- If you’re planning on growing your potatoes in rows, then you’ll need to dig a trench or drill about 6” deep. This allows you to cover the tuber with about 4” of soil.
- The soil should ideally have a pH5-6, so slightly acidic and be rich in humus. If you weren’t able to dig in compost to your soil in the autumn, then do so as you dig your trench.
- Plant the tubers in the base of the drill, about 12” apart for earlies, 12-16” for second earlies and 15-18” for main crop varieties.
Now there is a choice of methods, you could either
- Cover the seed potatoes by using a rake or hoe to draw the soil over them and form ridges over the rows.
- Provided soil is moist you shouldn’t need to water at this stage.
- The first shoots should emerge from the ridges after 3–4 weeks, depending on which type of potato you’re growing. The rows should be ridged up again to cover the shoots
- Earth up two to three times as the foliage reaches approximately 6-9 inches in height. This stops any potatoes that grow near to the surface from turning green and inedible.
- Cover the seed potatoes by using a rake or hoe to draw the soil over them and form low ridges over the rows. This is to help you to remember where you’ve planted the potatoes so it is only a low ridge.
- Provided soil is moist you shouldn’t need to water at this stage.
- Now cover the whole area where there are planted potatoes with black membrane or plastic. This is to prevent light getting to the tubers and acts in the same way as continually earthling up the ridges.
- Using membrane or plastic across the whole area also reduces weeds – and therefore weeding. The membrane is permeable to water whereas the plastic isn’t, but should retain more moisture, assuming the soil was wet initially.
- The first shoots should emerge after 2-3 weeks, depending on which type of potato you’re growing. You’ll need to watch out for these, as you’ll then have to cut holes for the top growth to come through the membrane or plastic.
Tip for best use of space: sow some quick growing salad seeds such as rocket or baby lettuce in between your rows of main crop potatoes.
Planting to harvest times for Potatoes
Early potato varieties take about 100-110 days to mature
Second earlies take about 100-120 days
Main crop potatoes take about 120 -140 days
Pests and Diseases
Blight, eel worm and slugs are the main problems. Main crop potatoes are more prone to blight than early varieties. Growing potatoes in a sack or container makes slug control easier.
There will be a blog about these pests which affect tomatoes as well as potatoes next month.
Harvesting and Storing your home grown potatoes
Again, I will return to this topic when its time appropriate. Basically, you harvest or dig up your potatoes when the foliage turns yellow and dies back.
I will also look at methods, for storing your grow your own fruit and vegetables later in the year. Both traditional and modern methods, appropriate for the domestic gardener where time and space may be limited.
In the meantime, get chitting!