How to sow and establish a high-yielding kale crop

Monday 11.05.2020 , News

Kale is a valuable crop for its high digestibility and a long utilisation period. Animals can utilise the entire plant and it serves as an ideal late autumn/early winter feed for cattle or sheep. It also provides a solution to overcoming late season grazing deficits.

Kale has the potential to give the greatest yield compared to a hybrid brassica or forage rape and should be sown in May/June in order to optimize the yield of the crop.

A crop of Maris Kestrel kale sown in May or June, can yield in excess of 10 t DM/ha and has exceptional digestibility and a high leaf:stem ratio. This can result in a crop that can be fully utilized by the animal, meaning animals can graze both the stem and leaf.

Other kale varieties, while may appear higher-yielding, are often made up taller with less digestible stems. This means much of the crop is not grazed by animals, and such varieties are more suited to bird cover.

Maris Kestrel kale

  • Outstanding leaf:stem ratio = high quality feed
  • Vigorous early growth
  • Expected yield 10 t DM/ha
  • Metabolisable Energy: 12.5-13.5 MJ/kg DM
  • Sow in May/June
  • Sowing rate: 2.5 to 3 kg/acre if drilled; 3.5/4.0 kg/acre if broadcast

Site selection

When choosing a field for growing forage crops for out-wintering, choose a field that will dry out quickly and that does not have an extreme slope.

In a site that is slightly sloped, it should be grazed from the top down, to avoid excess mud at the end from water running down.

The field should not be close to water courses or water supplies. Ideally, choose fields where grass production is falling and it can be incorporated into a grass reseeding program next time around.

Club root is a threat to brassicas, so a one-in-five-year rotation is advised to keep club root levels low. All varieties are prone to club root if a proper rotation is not implemented.

Sowing advice for kale crops

It is always advised to soil test prior to sowing as brassica crops will perform best under good soil pH and fertility status.

Bear in mind, that kale and such brassicas like soil with a pH >6.2, ideally 7.0, and fertile soils of Index 3 for P and K. If min-till method is being used, a minimum of 2 bags of gran lime will be required.

Prior to sowing, the old sward should be sprayed off with glyphosate. Kale is generally sown into a cultivated seedbed, but can also be direct drilled or broadcast, however, if broadcasting, you will need to increase the seed rate.

Seeds should be sown into a fine, firm seedbed at a maximum depth of 10mm to ensure uniform germination and rolled well after sowing.

Positioning bales in the field during the summer months or at the time of sowing will avoid machinery travelling the field in winter. Therefore, this reduces soil damage and workload at that time.

Fertiliser requirements

Brassicas have a high requirement for N and P, and an adequate supply of these nutrients is critical to maximising the yield potential of the crop. It is important to be mindful of remaining within your allowances as per the nitrates directive and the best advice is to split the fertilizer application so as to get better utilization from it.

For advice on sowing kale or other brassica crops, talk to our grass and forage production experts.