Article written by Emma Urquhart

Sustainability is a bit of a 'buzz' word in today's culture and is thrown at us from all directions. So what does it really mean? Well, in terms of environmental sciences, it is maintaining a long term ecological balance by using methods that won't deplete or damage our natural resources. In our vegetable garden? Well it's the same thing. If you think of your garden like your bank account, and you want to keep drawing money, you need to deposit money first. In the garden, you need to add nutrient to your soil if you want your plants to produce yummy edibles for you.

The simplest method that we have all heard a lot about is composting our garden and household waste. The key to this is variety – manures, lawn clippings, shredded paper/card (worms love this), wood chips, food scraps etc.. this will give you a diverse range of nutrients. I add a few spades full of garden soil every now and then to my compost bins because this helps introduce living microbes (and some worms) which all speed up the breakdown process.

Before you add your home compost to your vegetable garden it's a good idea to test the pH levels. Most vegetables like a pH of 6 - 6.8. However, often partially broken down compost tends to be more acidic than we would like, to remedy this you can either let it sit longer to break down or you can add some lime to your soil when you add your compost.

Other methods are growing cover crops and crop rotation. Crop covers, also referred to a green manures, can either be grains, brassicas or legumes. Grains add high amounts of roughage to the soil when dug in, brassicas have the ability to draw nutrients into the top soil from deep down and legumes contain nitrogen fixing bacteria in nodules on their roots which convert atmospheric nitrogen to an accessible form in the soil. Cover crops can either be dug directly into the soil once grown or harvested and added to your compost. Mustard is a popular cover crop for most home gardeners because it is quick growing, easy to dig straight into the soil, high in nitrogen, and contains high levels of glucosinolate which repels the dreaded wireworm.

Crop rotation not only helps with soil fertility, it all so helps with controlling diseases. A four year rotation is recommended because some vegetables (eg, carrots) like the soil to be broken down to grow well and others like a more fertile soil. For example: on a garden with lots of freshly added compost, grow potatoes first (they like heavy, fertile soils), followed by legumes and brassicas (legumes add nitrogen), followed by tomatoes and lettuces (which take a lot from the soil) and finally root vegetables (they don't like rich heavy soils). At the end of the root vegetable rotation add heaps of green manures and compost to replenish the soil, if you have the space, I like to grow a cover crop and let the garden bed rest for a rotation. This gives the living ecosystem in the soil a chance to recover.

Staggered planting will allow you a more continuous supply of produce through out the season. Planting for a continuous supply works well for most leaf and root vegetables and all our seed packets say how long it takes for individual vegetables to reach maturity. This means you can work out when you need to be sowing some more. For example with lettuces, which nearly all of us grow, they take about 6 weeks to reach maturity from seed, so you would want to be sowing more seeds every 2-3 weeks. That way when you are pulling out the old lettuces there are younger ones coming in ready to eat.

Vegetables like tomatoes, cucumbers, courgettes, etc you can carefully harvest the individual fruit once ripe and the plant will keep producing more, so as long as you feed them throughout the season they will keep producing. These types of vegetable wont need to be re sown at different stages through the season.

I've been experimenting with broccoli this last season. It's an annual so usually after cutting the head off, I pull the whole plant and replace it. I read that once the main head has been harvested then the side buds (found at the base of the leaf) produce more smaller broccoli heads. Well, after this second harvest of smaller heads I put the goat onto them to clean up the garden for the next crop. After the goat mowed off the broccoli nearly to the base I ran out of time and never got the garden cleaned up – more broccoli formed – small heads, but still enough for a feed. They are still going! (poorly and do need removing for this season's rotation) however, every now and then I'm harvesting a few heads from them which I'm pretty happy about since they have had no loving care what so ever. This just goes to show that sustainability can come in ways you wouldn't expect so always be on the lookout for more opportunities in your own garden!