Forage Kale

Why Grow Forage Kale?

Low cost option for finishing lambs
Buffer feed for dairy cows during dry summers
Flexible utilisation period
Excellent crude protein content
High yields and economical to grow
Outwintering systems
Highly rated game cover crop

Soil Type and Site Selection

Kale grows best on a medium loam soil with a pH of around 6.5. It needs a well drained soil which is not compacted. If you have to grow kale on heavy soil remember strip grazing may be difficult during very wet periods.

Seed Bed

A firm, fine and level seedbed is required and this needs to be achieved with minimum moisture loss, especially on dry soils.


Sow mid April – mid July. Broadcast at 2kg per acre or drill at 1-2kg per acre (2.5-5kg per ha).

The target is 70 plants per sq m. Good establishment and timely sowing usually give the best results.


Kale is a fast growing crop which will thrive when provided with plenty of organic material like slurry or FYM. Apply P & K fertilizer to seedbed. The N may be split between the seedbed and a top dressing once the crop reaches 15-16cm.

SNS Index 0 1 2 3 4 5 6
Nitrogen (N) 130kg/ha 120 110 90 60 0-40 0
Phosphate (P2O5) 110 80 50 0 0 0 0
Potash (K2O) 260 280 200(-2) 170(+2) 130 0 0 0

Data source DEFRA Fertiliser Manual (RB209)

Weeds, Pests and Diseases

Both pre and post emergence products are available for weed control. Good weed control during establishment should allow the crop to grow away well and achieve its full potential.

Especially in dry years when establishment is slow, flea beetle can cause considerable damage to young seedlings. Crops should be monitored regularly and where possible Cruiser treated seed should be used to give some protection early on. This must be drilled. In bad years a follow up spray may still be necessary. For those broadcasting, even closer monitoring is required to make sure the crop is protected as soon as it emerges.

Slugs can be a problem, especially in direct drilled crops, the application of slug pellets may need to be considered. Also be aware that both rabbits and pigeons can be a major problem under certain circumstances. Caterpillars are not usually a major problem unless infestations occur.

Clubroot is the main disease threat. It is soil borne so best controlled by good crop rotation. A gap of three years between any brassica crops should be adhered to as a minimum. However some varieties are now available with excellent resistance.

Alternaria and mildew can effect crops but are rarely a major problem. However once in a while they can devastating so should be kept an eye on.


The traditional method is to utilise the crop fresh, either by strip or zero grazing.
Strip grazing behind an electric fence which should be moved once or twice a day. Allow 3m per cow and an area of grass to run back on.

Zero grazing, cutting the crop with a forage harvester, will secure the maximum use of this excellent green feed, with minimum waste. The forage can then be fed from a forage box or behind a barrier.

As with all brassicas , feeding should be introduced over a two week period. Experts suggest that kale should provide no more than 30-35% of the daily dry matter intake for dairy cows.

Outwintering, Kale has been used very successfully in outwintering systems, often with the addition of big bale silage placed in the field prior to sowing.

Kaleage, although not as popular as in the recent past, ensiling kale can also provide a useful winter feed.

Typical Yields / Feed Quality
Average dry matter yield 8-10 tonnes/ha
Average fresh yield 60-65 tonnes/ha
Dry matter 14-16%
Crude protein 16-17%
Digestibility 70-75%
Metabolisable energy 10-11 MJ/kg DM
Typical Cost / Value
Cost per ha £496
Cost per tonne fresh weight £7
Cost per tonne utilised DM £67
Relative value £/t DM £133
Cost per litre of milk 2.8p
Cost per kg/live weight gain 18.8p

Data source: Kingshay Forage Costings Report 2010