Rob’s summertime recipe is made up of comfrey, stinging nettles and cleavers (bidibidi). This combination is high in potassium and low on nitrogen which is exactly what hungry summer-fruiting veges like tomatoes, cucumbers, peppers, aubergines (eggplants), zucchinis (courgettes) and melons thrive on.

He makes up 200-litre drums, but home gardeners can use a container that’s around 20-litres in capacity. Push the green material down as hard as you can into the container till it’s full to the top, add water, put a lid half-on (so the gases caused by the fermenting process can escape) and leave for a month. At this stage it will be a black liquid. You may notice hoverfly larvae when you take the lid off – they are totally beneficial for your garden.

After a month or so give the mixture a stir. The woody material that you dredge up can be used as a mulch. Dilute the liquid to the colour of weak tea and apply to the leaves as well as roots of plants. This mixture will almost double a crop of potatoes.

A winter recipe will include fish heads, animal manure along with seaweed and weeds like puha, thistles, plantains and cleavers. This winter brew is good for kale, silverbeet and other green leafy vegetables which need nitrogen rather than potassium that summer veges like.

Another great way to feed your soil is by applying Black Gold. There are three ingredients in Black Gold: coffee grounds, seaweed (preferably kelp – the big straps – because it has many more minerals than seaweed) and an animal manure. We suggest you make it in a black plastic rubbish bag to attract the heat. We layer in firstly coffee grounds, then kelp, then animal manure, then repeat till the bag is full. Don’t seal the bag as we want air to get in. Leave it in a sunny place and every now and then turn it over to aerate. It’ll take about 6 months till it’s ready to use.

Camera/Editor: Ollie Logan