How To Grow potatoes in bags or land

Potatoes are one of the most popular vegetables today and have a ready market if properly grown. Communal farmers have become one of the major growers and suppliers of the vegetable to the market.

To help improve quality of the crop Agropreneur Zimbabwe has the following easy to follow tips on how to grow potato. The following tips were sourced from ZFU and USAid.

At the appropriate planting time, set three tubers on top of a 15-20cm layer of good quality compost in each Potato Growing Bag and then cover the tubers with a further 10cm layer of compost and fertiliser.





As the plants grow and shoots emerge above the surface, add more compost to the potato growing bags to cover the shoots and then repeat as needed until the compost is about 5cm below the top of the bag.

Seed variety:

There are more than 400 varieties of potatoes to choose from. The best way to find the best variety is to enquire from established potato farmers in your area.

Seed varieties resistant to late blight are recommended.

The most common potato varieties grown in Zimbabwe include Amythest, Mont Claire, BPI, Jacaranda, Opal and Emerald.

First early potatoes take some 10 weeks to mature, second earlies take

13 weeks while the main crop would take more than 20 weeks Soil and Land preparation:

Potato can be successfully grown on most types of soil but averaged loamy soils with adequate organic matter are most suitable.

Land should be deeply ploughed and harrowed to create fine top soil conducive for root penetration. Soil boulders and stones should be avoided as they reduce root contact with soils and result in deformation of the tuber. Heavy clays and other hard soils may also cause the same tuber deformation effect.

If farmers really have to use heavy clay soils they have to be well drained more so during rainy seasons.

Harrowed and lose soils help ensure sufficient oxygen for roots which is necessary for healthy tuber growth.

Planting and spacing of potatoes:

Potato tubers are placed in rows either manually or by mechanical means. Recommended spacing when planting seed which will have sprouted between 5 to 15 millimetres long is in rows some 20-30 cm apart.

Recommended row to row spacing is between 60cm to 120cm.

Farmers would be advised that spacing is determined by soil fertility and seed size among other factors.

Under irrigation tubers can be planted 7-10 cm deep. For dry land the depth can be increased to some 15cm.

After planting ridges should be created to cover potato tubers.

Planting season:

Potato crop can be planted in summer or winter.

The summer crop is planted in November and harvested around March just close to the end of the rain season.

The first winter crop is planted between February and April. It matures before the frost period.

The second winter crop should be planted between end of July and early August after the risk of frost has little chances to attack the crop.

Pre-planting watering or irrigation helps ensure uniform germination of the crop.

The second irrigation should be administered a week after the first.

Further routine irrigation will be as per need.

Irrigation should stop two weeks before harvest to allow for firming of tubers.

Farmers should bear in mind that potato crop requires a lot of water and sun.

Fertilisation:

Basal Compound S and Compound C are recommended and should be applied as per specifications of the manufacturer. Top dressing should be applied once between rows or per plant before final earthing up.

Top dressing of Sulphate of Potash should be applied at flowering stage and two weeks after flowering.

After applying top dressing potatoes should be ridged up to some 20 to 30cm high. Farmers should note that the first ridging also works as weed control while the second covers cracks created in the soil by growing tubers.

Earthing:

Earthing which is basically the drawing of soil up around the plant prevents new tubers from growing and turning green before eventually becoming poisonous. Buried stems will also develop more potatoes.

Weed control:

Weeds compete with the crop for water, nutrients, light, growing space and may cause substantive yield loss.

Weed control can be by use of unsophisticated methods such as hoe cultivation, mechanical and chemical methods.

Chemicals used in this respect include EPTC, Topogard, Dual and Sencor.

Pests:

Namatodes:

There are three main nematodes species that affects potatoes. These are Meloidogyne, Radopholus simils and Pratylenchius.

Potato tuber moth:

Tuber moth larvae cuts off nutrients flow in plant tissue after creating tunnels in plant tissue. This results in wilting of the plant.

Tuber moth can be controlled by ridging the plants up to 250mm, use of chemicals such as Azodrin or Navacron.

Aphids:

These are small greenish sucking pests which causes wilting and curling of leaves.

Azodrin, Malation and Thionex spraying curtails the pests.

Cutworms:

Cutworms are darkish greasy caterpillars that normally feed at night.

They usually attack the crop at its early stages. They chew the plant at surface level.

Chemicals such as Karate, Thiodan and Carbaryl are the most recommended for the worms.

Cold weather conditions also help tame pests and insects which would otherwise destroy the crop.


Fertilisers
What do I use to sprout seed potato and how long does it take before planting it out?
Seed potato can be forced to spout by a growth hormone known as Gibbelleric Acid (GA). Seed potato is dipped into water treated with GA for about a minute, left to dry and placed in chitting trays. The period it takes for the seed potato to sprout is mainly influenced by temperatures. It generally takes not less than three weeks for tubers to sprout and be ready for transplanting. (Can be obtained from ZFC)

Storage:

After harvesting potatoes are stored to maintain tuber quality before they are supplied to the market.

Storage should be good enough to avoid excessive dehydration, sprouting and decay. The storeroom should be well ventilated, vapour proof in the inside, sufficient humidification, adequate insulation and the room or structure should be routinely checked for recommended conditions and temperature.

Tubers should be kept in the dark since light would cause greening which is not desirable.

Harvesting:

The crop will be ready for harvesting when most of its leaves and stem have dried up. At this stage the potato skin will have hardened.

Market:

Potato markets in Zimbabwe are either formal or informal. The formal market is made up of giant traders such as FAVCO, Harare Produce Sales and Sun Spun among others.

The informal markets include most notable ones such as Mbare, Chikwanha and Machipisa.

Harvested potatoes can also be reserved as future seed.