Great grassland depends on timing and technique
With thorough soil preparation and a good sowing technique, you can get many more of your forage seeds to germinate and grow.
Your soil must be ready
A productive sward starts with well-prepared soil. Before you sow, prepare your field for seed germination and subsequent plant growth. Plough and harrow the field, then follow up by rolling to keep the surface moist. This vital routine creates an even seedbed with enough moisture for quick and even germination.
The best times to sow are spring or late summer/early autumn when soil temperatures and moisture levels are just right for good and fast germination.
Good seed-to-soil contact is essential
The diagram below represents seedlings in three seedbeds. The darker band shows where the moisture is in the soil. Bed number 1 has established well because the seed has been sown evenly and to the right depth to reach moist soil. In bed number 2, poor harrowing has created an uneven distribution of moisture. Some seeds have developed well, but others failed to reach any moisture. In bed number 3, establishment was poor because preparation went too deep. If rain does not come soon, very few plants will develop.
When the soil is dry or light, drilling is often more successful than broadcasting. However, drilling in rows leaves more room between the rows for weeds to grow. One way to reduce this effect is to drill twice over with drill lines crossing at an angle. Broadcasting generally gives better distribution and ground cover, but the soil must cover the seed and the seed must make good contact with moisture. Whichever method you choose, you will need 25 to 35kg of seed per hectare.
Keep seed depths shallow
Do not seed too deep. Grass seeds should never go deeper than 1 to 2cm; clover seeds should not go beyond 0,5 to 1cm. In a pure stand, ryegrasses can go deeper – 3 to 4 cm should be fine. In the main, it is legumes and grasses with small seeds that respond badly to deep sowing. The table below shows, for a range of forage species, how depth of sowing alters the percentage of seeds that develop.
A good result: 1 out of every 5 seedlings survive
In a good sward establishment, 15 to 25% of the seedlings will survive for several months. For the best results, aim for around 300 to 500 plants per square metre and 10 to 12 tillers per plant. That is equivalent to 3.000 to 6.000 tillers per square metre.
|Typical seed weight, g/1000 seed||Seeding depth|
|1 cm||2 cm||4 cm||6 cm|
|Italian ryegrass, T||3,8||76||73||57||32|
|Italian ryegrass, D||2,2||75||68||43||13|
|Perennial ryegrass, D||2,0||62||63||45||11|
Data gathered during pot trials in Denmark.