The Margan Garden - Cover Crops

If you are walking past a farmer's field during its off-season, it may just be lying fallow and inactive. However, if there is another crop growing that isn't the typical crop for the farm, the farmer has likely decided to implement cover cropping. At Margan, we employ cover cropping in the vegetable garden and the vineyard. 

So what is the purpose of using cover crops, also known as green manure or living mulch? Perhaps weed suppression is the most instantly appealing benefit of cover cropping to most gardeners. Weed infestation is much less severe in the colder months, but if we can almost entirely eradicate their presence from our garden beds, why wouldn't we? Weeds are just plants in the wrong places, and so essentially, they require the same things that crops do – nutrients, water, and sun. If the weeds are successfully outcompeted for these elements, they will struggle to grow; Jerusalem Artichoke is an example of a crop that does this in our garden. These quick-growing tubers take up soil space and form a leaf canopy that shades the soil beneath them. By doing this, they make it difficult for weeds to thrive. Many cover crops grow so successfully that the garden bed they are occupying remains almost weed free. 

Secondly, cover crops are fantastic for building soil health and drainage. Clover has numerous varieties, cowpea, hairy vetch, and peas are all nitrogen-fixing cover crops. They draw nitrogen from the air and feed it to the soil via their root systems. Nitrogen is an essential nutrient for healthy plant growth, so increasing the amount of nitrogen in the ground through an inexpensive method such as cover cropping is very beneficial. In addition to the nitrogen these plants provide to the soil, once the new season of planting approaches, cover crops can be cleared from their bed and thrown into the compost pile to decompose into nutrient-rich compost. 

A common issue for many growers in Australia, especially if an area has suffered from drought and has clay soil, is soil compaction. If soil is compacted, plant growth suffers as roots struggle to access nutrients and water is not held efficiently in the earth. Winter rye and daikon radish are cover crops with deep root systems which are highly effective at loosening soil in preparation for the upcoming season. 

Here at Margan, we seeded daikon radish in our pumpkin patch once all of our pumpkins had been harvested. This loosens the soil, ready for either another pumpkin patch or a potato patch. And the best part is that our kitchen will have heaps of daikon radish to turn into kimchi!