Strength in diversity
Ihave been growing my staple vegetables in central Tākaka for over 14 years now within a growers group called Fertile Ground Collective. In recent years, we have experimented with more intercropping of two or more crops together. We’ve done the three sisters of sweetcorn, dwarf beans and pumpkins. Dwarf beans are grown with various summer brassicas down the middle of the bed. And we’re trialling growing a variety of onions with carrots in an attempt to ward off the carrot rust fly. At home, I grow the more intensive crops such as tomatoes and climbing beans in poly-cropping guilds. These have stacked functions and diversity is key. A great way to improve soil fertility is adding compost, vermicast or rotted manure while preparing beds. This adds valuable nutrients, carbon and microbes to the soil. Another way is to return to the soil green crops for soil organisms to eat. Winter green crops such as lupin and vetch, oats, mustard or phacelia are chopped down a month in advance of planting time to enable full integration into the soil. Covering with black plastic speeds this up. The same process can be applied to weedy beds to get them ready for planting. For spare beds, these can be sown in summer green crops such as lupin, crimson clover, oats and buckwheat. Natural minerals are also important. Having followed the Kinsey-Albrecht method of soil testing and subsequent re-mineralisation with organic fertilisers according to the results, my soil and crop health has definitely improved. I recommend a vege bed width of 1.2m to enable easy access from both sides. Following some sort of planting plan helps organise the number of crops needed, plus will help you plan your seasonal plant timing, spacing, fertility needs, and crop rotation to enable good results. Root crops such as carrots and parsnips are sown into beds (or strips) that have been lightly surface tilled to “flush” the weeds out. With beans and pumpkins, these are planted when the runner beans resprout, which should be around now, or when soil temperature is 16°C. The biointensive staggered pattern planting technique works well to ensure plants are packed in for maximum efficiency of space. Main crops are planted first, followed by fast-growing catch crops such as lettuce to fill the bed, eliminating the need for much weeding. My favourite hand tool for planting (and weeding) is the Japanese Niwashi. Main crop potatoes are best planted no later than the end of October now that the psyllid insect pest is about when temperatures are more than 20 °C. Plant potatoes (ideally following a green crop) into a shovel hole alternating down the bed so there are two rows, followed by soil and compost. They are mounded with soil as they grow, and mulched with grass and hay from adjacent field through the growing season. Use insect cloth to protect against psyllids. Many crops needing extra warmth (and in case of late frosts) such as beans, zucchini and tomatoes are cloched with Mikroclima cloth. This lets some rain and air through, and can be opened during sunny periods. Heat-loving crops such as melons, eggplant and capsicum do best with black weedmat or black plastic (along with cloching) to increase thermal mass resulting in better yields. We plant melons where old compost piles were too. Herbs and annual flowers are in the planting mix for soil health, plant interactions and to attract beneficial insects. My favourite are alyssum, marjoram and parsley on the edges, and borage, calendula, marigold, basil and phacelia in the bed. Even small weeds such as speedwell and henbit offer good edging, keeping valuable mulch on the beds during the coming summer months. In the orchard, fruits are ideally grown in guilds too. Forest gardening, reported on regularly in NZ Gardener by Robert Guyton, is the logical way of managing an orchard, providing health benefits to soil and plants, and a good yield of fruit. Now is a good time to sow beneficial insectary plants such as cow parsley, fennel, alexander, angelica, and annuals such as phacelia, parsnip, parsley, borage and nasturtiums. Comfrey, my favourite herbaceous perennial for the orchard, is best planted now, just inside the trees’ drip line. Take root cuttings and place in a hole along with a dollop of rotted manure and cover with soil. If the orchard hasn’t been fed, do it now with chippings from pruning hedges, shelter and ornamentals. Fruits, especially berries, stone fruit and subtropicals such as citrus and avocados, love woody mulch. Ongoing mulching also helps you mow the lawn less. Spraying fruits with seaweed liquid fertiliser also adds much needed micronutrients for the growing season. Growing our food has never been more important in these uncertain times.