Propagation
Turnip propagation is from seed.Planting Method
Turnip planting can be done by direct seeding or by raising seedlings and planting out the seedlings. Planting in both cases can be done by hand or by mechanical planters. When direct seeding is done, the turnip seeds are placed between three and five centimetres apart to ensure crop density.
Once they are settled about three to four weeks after planting, the rows are thinned out to the desired plant density. Turnip planting is done in uniform plant rows and widths or in tram lines with access rows between the tram lines for workers and vehicles. Some turnips are planted on level ground while others are planted on raised planting beds.
Spacing
Turnip plants should be spaced 15 cm to 20 cm apart in rows that are 50 cm apart. This should result in between 100 000 and 120 000 plants per hectare.Sowing and Planting Time
The turnip is a cool climate grower so plant at a time when the main growing period will experience cool weather.
For harvesting during the South African spring, planting should be in March and early April so that the plant can strengthen before the winter cold sets in and the first frosts arrive.
Spring plantings can be done in August and September but should be harvested before the excessive summer heat as this will spoil the turnips.
Growth Period
The growth period from when the turnip seeds are planted to root bulb harvest is between ten and twelve weeks. Turnip greens or the leaves can be harvested from six to eight weeks if the plant is strong enough and the roots are developing well.
Remove only the outer leaves so that there is enough foliage left to keep the plant growing and roots developing. Cool the leaves quickly after cutting.
Fertilization
A soil sample must be taken and professional recommendations sourced to ensure correct nutrient applications. The following recommendation is a norm that can be followed when fertilizing turnips. In the week before planting of the seedlings apply 400 kg of 2:3:4 (30) per hectare when preparing the plant bed and disc into the top 20 cm of soil.
This provides nutrients immediately after planting and will provide the plant with energy for a good start and also to assist with the stress created during the transplant. If sowing seeds, apply the first application along the plant row as soon as the new plants start to surface. Two to three weeks later, broadcast the same as the first application along the plant rows.
After a further two to three weeks, a third application of 350 kg per hectare of LAN (28) can be broadcast along the plant rows. This should be ample for the crop to reach maturity and be ready for harvest. Remember to practice weed control as weeds will rob the plant of the nutrients that are being administered.
Irrigation
To ensure good yields and good taste it is essential to avoid moisture stress with turnip production. Before planting, make sure the soil is moist but not waterlogged.
Sow or plant turnips into moist ground and provide a light irrigation after planting for both seeds and seedlings to settle. The most important part of irrigation is having a system to ensure the soil profile required by the turnip crop remains properly irrigated.
This can be done by hand with a spade or augur or by installing soil moisture meters to provide the information as to the soil moisture tension or stress. After the plants have settled, a weekly allocation of 30 mm should be sufficient throughout the cooler months of the growing season and 40 mm to 50 mm in warmer weather.
Split this into two or even three applications throughout the week. Remember to reduce the irrigation if it rains and to increase irrigation volume and frequency during periods of high temperatures and high evaporation.
By Louise Brodie