Planting Potatoes

Planting Potatoes in the Garden
- chitting, planting & earthing up -

Planting potatoes in your garden is no effort at all when you consider the likely rewards - a magnificent crop growing right outside your door over the coming months.

On this page I'll explain the why, when and how of chitting potatoes before planting - planting depth and spacing, and about earthing up or hilling.

You'll find further information about potato gardening on the main plot.

The potato tuber is a storage organ that goes into a resting stage. Your dormant seed potatoes need to be 'woken up'. So about 6 weeks before planting potatoes start chitting the tubers.

As explained here, commercial potatoes destined for cooking may have been treated with sprouting inhibitors to prolong storage - hardly what a gardener needs. Choose seed potatoes to suite the season and your taste on this link.

Why Chitting or Sprouting 'Early' and 'Second Early' Potatoes Gets Results

Chitting potatoes simply involves leaving the tubers in light room - e.g. a window sill or conservatory - at a temperature above 4^oC but not too warm (below 10^oC). Then the potato tubers start to shoot out - more below on how to chit your potato tubers.

With 'Early' and 'Second Early' potatoes chitting has been found to have a positive influence on potato yeilds.

The shorter spring day length will stimulate your 'early' potatoes to form tubers. Once the message is sent it is remembered. So when planting potatoes in August for late harvests using 'earlies', chit them in spring and keep them dry - alternatively buy specially prepared seed potato for late harvests.

When chitted potato tubers go out in the cool they have strong actively growing shoots to give them a head start for growing the leaves and roots needed to make a good crop.

Chitting 'earlies' should start 6 weeks before planting potatoes - mine have been overtaken by 'second earlies'. I think you can give them a short spur in warmer conditions if they're slow to chit. Find more on how to grow the earliest potatoes on this link.

You Don't Need To Chit Maincrop Potatoes Before Planting

You can put the tubers straight out when planting potatoes of maincrop. The ground has warmed up and no advantage has been demonstrated for chitting.

This Upside Down Tuber
Shows the Stalk End

Upside down potato tuber showing stalk end and shoot end

Set tubers out
'rose end' up.

seed Potato tubers set out in egg boxes in the light for chitting or shooting.

A little longer than a thumb nail - the potato shoot is ready for planting at about 1 inch

This potato tuber has one strong thick shoot ready for planting

When too long they break off easily

Chitted potato shoots shouldn't be too long - they break off easily

Don't chit potatoes in the dark

Potatoes shoots in the dark are blanched

How To Chit Your Potatoes

All you need is cardboard containers such as egg cartons or an empty seed trays. The shoots are concentrated at one end of the potato tuber known as the 'rose end'. Notice that the opposite end has the scar where the stalk attached it to the mother plant.

Set the tubers in the box 'rose end' up - add name labels if necessary. Place the box in a light frost free place but not too warm.

Now a watering with liquid seaweed fertilizer is recommended by organic gardeners. You might repeat this at 2 week intervals. Liquid seaweed will strengthen the shoots and provide essential nutrients for healthy growth.

You want about 3 strong shoots per tuber. The more shoots left on the smaller your potatoes will be and vice versa. Try starting first earlies with fewer shoots as they produce smaller spuds anyway - and if you want big bakers from container grown potatoes reduce the number of shoots.

Most gardeners advise rubbing out the shoots that you don't want. But potato eyes have a way of growing back. It's probably better to carefully cut out the unwanted shoots with the point of a potato peeler - take a small chunk out of the flesh.

You can cut potato tubers into pieces that each contain growing buds. This practice is probably best restricted to main crop and it may produce a reduced crop. Leave any cut surfaces to heal in air for a few days before planting.

The potatoes are ready for planting when the shoots are strong and thick and about 1 inch long.

Ready For Planting Potatoes

Potatoes can go into garden soil about 2 weeks before the last frost. That's about how long it takes the shoots to come up. They can go in earlier if you protect them with fleece, or a tunnel cloche.

Planting potatoes of maincrops outside should probably be done by the end of April. After this time the longer days will delay the onset of tubers.

By late July and with the days shortening again you can do more potato planting. Remember to chit seed potatoes during summer that are intended for late August and September planting.

The varieties chosen for a Christmas harvest are specially prepared 'earlies' - you can get them from this link.

POTATO ROWS DEPTH AND SPACING

Tubers can be different sizes which effects planting depth. I suggest planting potatoes so the soil covers the top of the 1 inch long potato shoot by about 1 inch - no less. A 2" long tuber needs a 4" deep hole. In drier conditions plant a little deeper.

For 'First Earlies' plant 30cm (12") apart in rows 60cm (24") apart,
For 'Second Earlies' plant 37cm (15") apart in rows 75cm (30") apart,
For 'Maincrops' plant 45cm (18") apart in rows 75cm (30") apart.

Reducing space between rows will reduce the size of your potatoes. Better to increase the between-row space and plant a row of smaller crops such as broad beans in between.

Potato rows should ideally be orientated north to south. That way ridges warm up evenly on both sides - and the longest shadows fall into the wider space between rows.

PLANTING: When planting potatoes in rows, always use a straight edge such as a string line or a board with spacings marked off. A garden trowel or scoop are the right tools for making a suitably sized hole for planting.

PLANTING POTATOES IN FURROWS: With deep well drained and cultivated soil you can take out a furrow piling soil to make a ridge on both sides of the row. Place the tubers on the bottom of the furrow or plant them in a hole in the bottom of the furrow. Draw soil over the potatoes to cover as explained above.

This method allows you to turn a furrow into an earthed up ridge. It is easy to keep the potatoes well earthed up. You may get a bigger crop this way by keeping the tubers moist and well protected.

GROWING IN COMPOST TRENCHES Potato plants can be grown in well-rotted garden compost trenches assuming they're not saturated. Avoid raw unfinished compost which risks an attack by soil pests like millipedes or slugs.

Earthing Up Potatoes

As they grow the potato plants are 'earthed-up' (hilled) by drawing soil up the stems and forming a ridge along the row.

Use a draw hoe to keep piling soil into a ridge around the stems. This helps to prevent stems of some varieites from rocking and falling over. But importantly it keeps the new tubers moist and protected from sunlight.

Light turns potatoes green and underground stems destined to be tubers back into leafy shoots.

Earthing up also makes it less comfortable for pests like slugs.

Check these links.

Next > How to harvest your potatoes -

The Garden Seat - more books on growing and planting potatoes

You can make easy work of planting potatoes - with the
excellent tool on this link. You'll save loads of time - plant a larger area - and grow in tough soils.