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  • Green Manure Your Soil

    There are many ways one can improve the soil and one of the easiest is by sowing seeds of legumes and grains.  Using a mixture of seed varieties contributes to the success rate of the green manure. There are many benefits in using green manure and by using this practice it will add organic matter to your soil, fix nitrogen, plus assist in making available a broad range of nutrients.  Also it will help biological and worm activity while improving soil structure and also makes useful mulch.
    Legumes are able to produce small nodules that look like small pink sacs on the roots and the plant is able to access atmospheric nitrogen and fix this into the root nodules, which in turn improves nitrogen levels in the soil.  Certain Rhizobia for legume plants needs to be present in the soil for this process to work more effectively. To check if you Rhizobia are fixing nitrogen you can break one open and the inside should be a pinkish colour which tells you they are fixing nitrogen into the soil. If Rhizobia Nodules are not present on the roots then you need to obtain the correct inoculant for that seed type. These can often be found at your local produce store or online.
    Rhizobium on Mungbean Roots
    Grains tend to carry a lot more root mass and have a coarser stem that takes longer to break down in the soil and generally tolerates poorer soils.
    There are several methods that can be used for sowing.  Simply  broadcast the seed over prepared soil and rake in lightly.  Cover the seed lightly with mulch to reduce drying out and keep moist until germination takes place.
    The second method involves no cultivation of the soil ensuring you don't disturb the soil structure. This easy method can be done by broadcasting seeds over some existing vegetation such as a previously used garden bed where grasses are growing cut the grass over the top of seed providing a mulch cover. This method can take a little longer to germinate and it is not recommended with hard packed soil.
    To get the the best germination of green manure seeds try timing the sowing with a 2-3 day rain event and your seeds will germinate before your eyes.  If the area is low in nutrients, some organic fertilizer can be added to give your green crop a boost.  Most green manures will take 6-12 weeks to grow and could range in height from 30-90 cm, depending on the varieties used.
    To maximise the benefits of green manuring, make sure to turn your crop in just before flowering starts.  Methods used include turning in the vegetation with a garden fork, rotary hoe or slash firstly then turn in the soil with a fork or hoe. Planting can be done as soon as 2 weeks after turning in the green manure and to take full advantage of the nutrient rich green crop.
    What to Sow and how much?
    20 grams approximately of seed per square metre or for larger sowing use 500g of seed per 30m2. These are approximations and seed size varies greatly so using your own discretion will be beneficial.
    Spring to Summer
    Legumes – Adzuki bean, Cowpea, Lab Lab, Lucerne, Mung bean (Below Image), Soybean
    Grains – Amaranth, Buckwheat, Millet, Sunflower
    Sunn Hemp Green Manure
    Autumn to Winter
    Legumes – Chickpea, Clover, Fenugreek, Lupin, Vetch
    Grains/ Green Leaf Mass – Barley, Mustard, Oats, Rye Corn, Wheat, Silverbeet, Beetroot
    Where to buy green manure mixes?
    Greenpatch Organic Seeds has a large range of bulk grains available for green manure mixes. You can make up your own mix or buy our pre-made mixes which contain a nice balance of bulk organic matter growers and legumes for nitrogen fixation.
    View our Pasture Seeds collection to purchase.