Direct Seeding is a way of establishing vegetation by placing seeds directly into prepared ground where they germinate & grow without disturbance.
Because there is no need to plant seedlings it is the simplest & most cost effective way to establish native vegetation for shelter, screening, wildlife habitat, timber production or salinity control.
There are two main ways of direct seeding.
The Mouldboard Ploughing technique of ploughing then broadcasting mixed seed has been proven throughout southwest Victoria over the past two decades. This seeding method results in a dense, mixed, continuous cover of plants similar to natural bushland. This is the method most widely used by Direct Seed.
Other methods of direct seeding are also used, particularly in lower rainfall areas. These are based on the sowing of seed in straight lines and the use of residual herbicide. A seed box delivers seed at a pre determined rate into the rip line and the seed is then pressed into the ground with a press wheel. Machines used include the Hamilton Tree Seeder, the Eco Seeder, the Rippa Seeder, and variations on these. The features of this technique are trees established in rows and more economical use of seed. Direct Seed can supply seed & organise all required machinery.
Preparing the Site
The preparation of the site is all important in direct seeding. Typically for most situations the plantation area should be sprayed with Glyphosate (eg Roundup) in the spring to knock out competition. Where there are perennial weeds present additional spraying during the previous spring/summer/autumn is required. This extra spraying will help results in all sites. The grass should be grazed or slashed short before it is sprayed.
For machine seeded sites a residual herbicide is sprayed shortly before seeding.
Ploughing and Sowing
Ploughing with a mouldboard plough with skimmers will give the best result. Rotary hoes, discs or tyned ploughs are only suitable for very infertile sites where weed competition is low.
After the area has been ploughed, it may be necessary to roll it down with the wheels of the tractor, to get rid of any air pockets. Don’t flatten it as the variations in the surface, the 'lumps and bumps', give good protection and collect moisture for the emerging see heemrging emerging trees.
The seed mixed with coarse sand is broadcast over the whole area and then rolled in with the tractor wheels.
What sites are suitable?
Direct seeding is not recommended where there is a possibility of machine rollover. It is also not recommended for heavy cracking clay soils. In fact, the soil type has a huge effect on the success of any direct seeding. The easiest soils to seed are light loamy soils with low fertility. As long as moisture levels can be sustained over the first few weeks after sowing these areas should succeed without a problem. Heavier ground takes longer for the seed to germinate.
Where a lot of fertiliser has been used the competition from introduced grasses will be higher.
Most of our work uses indigenous (local native) seed because local native trees are best adapted to the wide range of conditions that the local climate can throw up. They have been refining their survival techniques for many thousands of years, and will survive wet years and dry years. They will progressively germinate over at least twelve months to take advantage of the best conditions.
Typically Eucalypts, Acacias and teatree are the core of the revegetation mix with sheoak, Solanum, tree everlasting and various grasses and sedges added.
However there are many situations where other species are used.
Spring is the best time for direct seeding in agricultural land.
Depending on the site and the seeding, August to November is the most common timeframe.
There is usually none required. The plantation once established does not require watering or weed control. However it should be monitored for pest animal browsing and establishment of aggressive perennial weeds such as kikuyu, phalaris or blackberry.
There will be substantial growth of weeds in the first year- this is normal. The direct seeded plants will grow through this.