Catch and forage crops: Yield, dry matter and GLAS approval

There are lots of different options when it comes to sowing forage crops. These options all vary in yield, dry matter (DM) and protein, while not all qualify under the catch crop requirement in the GLAS scheme.

Some produce large amounts of bulk which may be a good option for the winter ahead.

Crops with a low DM content are more suited to grazing, while crops with a high DM content, like vigorously growing grasses or cereals, may be a good option for ensiling.

Below are some of the options available this season. It is now too late to sow kale or swedes. However, Redstart – a hybrid brassica which is a cross between rape and kale – can be sown into August.

  • Fodder rape: Fresh yield: 25-29t/ha; DM: 12-13%;
  • Stubble turnips (not GLAS approved): Fresh yield: 35-45t/ha; DM: 8-9%;
  • Westerwold ryegrass (not GLAS approved): Fresh yield: 17t/ha; DM: 27%;
  • Italian ryegrass: Fresh yield: 12t/ha; DM: 27%;
  • Forage rye: Fresh yield: 22t/ha; DM: 11%.


Farmers sowing catch crops for the GLAS (Green, Low Carbon, Agri-Environment Scheme) must sow a mixture of seeds. The species in this mixture must be approved under the scheme. Mixtures can be purchased pre-prepared or farmers can choose their own mix.

GLAS catch crop mixtures must contain at least two species from the list below; they should be sown at or above the seed rate outlined.

GLAS approved crops and minimum seed rates:
  • Buckwheat: (30-40kg/ha);
  • Clover – crimson/berseem: (10-15kg/ha);
  • Forage rape: (3-5kg/ha);
  • Mustard: (6-10kg/ha);
  • Oats: (75-100kg/ha);
  • Black oats: (75-100kg/ha);
  • Phacelia: (2-5kg/ha);
  • Rye: (65-80kg/ha);
  • Tillage raddish: (5kg/ha);
  • Vetch: (12kg/ha);
  • Leafy turnip: (5kg/ha);
  • Peas: (30kg/ha);
  • Beans: (90-100kg/ha).

Crops sown under the GLAS scheme cannot be grazed until December 1.

Crops that are not GLAS approved:
  • Westerwold ryegrass;
  • Italian ryegrass;
  • Lucerne;
  • Clover – white/red;
  • Chicory.