Category Archives: Potaoes

Potato harvest August 2020

The six plants produced 13Kg of potatoes from 0.88 sq. metres. That is equivalent to 14.75Kg per Sq. metre or 147 tonnes per hectare. The average farm yield is around 40 Tonnes per hectare. I am not suggesting that farmers should divide their fields into square metre plots but it does show that small scale growing can produce a significant amount of food.

The tops did suffer from blight but it was not bad and did not go down into the tubers. That is exactly how we expected Saro Mira to behave having grown then for many years.

The spuds will be stored in hessian sacks in the cool, dark shed until early 2021,

Frost warning!

The Met Office is forecasting frosts in the next few days with temperatures here predicted to fall to 1C in the early hours of Monday 11 May and Tuesday 12 May and 3C on Wednesday 13 May and Thursday 14 May. The wind  will also be back to N or ENE so it will feel very much colder.

Use fleece to cover any tender plants. Note: fleece is not a blanket, it will not keep plants warm but it will stop ice crystals forming on the foliage which does the damage.

Our Sarpo Mira have just broken the surface, they will need covering

If you have potato tops through then cover them with soil, straw or something similar to stop them turning black and rotting – see pic below.

Frost damaged potato tops

Potato planting

Easter is the traditional time to plant potatoes, but it is better to choose your own time when the weather and soil conditions are right. We planted ours yesterday after making a deep raised bed and filling it with a mixture of soil and compost.

The bed filled with soil and compost

The soil used in the bed came from a turf stack from part of the lawn we removed last year. The turf was stacked grass side down against a wall. There was a good amount of fine topsoil which was mixed with compost from and an old bin we inherited. It took around 12 wheelbarrow loads to fill the bed.

Digging the holes for the seed potatoes

Chitted tubers ready to plant

Ready to plant in the hole

Ready to be filled in

The potato tubers were planted in holes about 200mm deep (8 inches) with the chits pointing up. The chits will grow and form the leaves and stems, so it is important to handle the tubers carefully.

We never use the trench method of planting, i.e. digging out a trench then placing the potatoes in the bottom and then filling in the trench. That is too much soil disturbance and too much work if you have a big bed.

As the first shoots appear cover them with soil to protect against frosts as the new growth is very tender. This is known as ‘earthing up’ and it also helps to increase the yield. The other thing to remember is that potatoes need lots of water so keep them moist all through the growing season.

The general gardening and allotment wisdom is that harvest time comes soon after flowering when the top growth have died off.  We grow a variety called Sarpo Mira which behaves differently to ‘normal’ spuds. The tops do not die off and keep growing right through the autumn if you let them.

Sarpo Mira will continue to increase in size until they are huge and become hollow if you are not careful. The best way to tell when to harvest is to look at the size of the spuds in the ground. Carefully dig some up and see if they are the size you want and if so, harvest the rest. When we have grown this variety before we have harvested about 16 weeks after planting.

Some notes about growing  Sarpo

  1. If you get brown spots on the leaves do not automatically assume that it is blight! See my blog post of 19 July 2009. It is more likely to be a nutrient deficiency.
  2. If they do get blight do NOT cut off the tops .At a trial in Wales this year where Sarpo were the only variety left standing when everything else had been wiped out by blight. They had some patches of blight on the leaves but the researchers say that the plants can continue growing for ~3 months after infection. The blight does not seem to go down into the tubers so the harvest is not affected.
  3. ‘Mira’ is a very heavy cropper so needs feeding throughout the growing season.
  4. The tops do not die off after flowing like other varieties so do not wait for that to happen before lifting. (They can continue flowering for weeks!) Check regularly and harvest when the tubers are the size you want. I would advise against leaving them into the ground until autumn as the tubers can become massive and hollow.

Got to this web page for a list of stockists

Read more about the Sarpo story here.