Down to earth: Healthy soil
Now that spring is looming and bulbs are blooming, take a look at your soil and suss out whether it’s healthy or not.
With a plan of all the crops you want at hand, some beds may need special attention if you want pumping, abundant produce. A soil’s health can be measured in terms of its physical, chemical and biological properties. Here are some indicators of a healthy soil:
Good soil structure (or aggregate stability): The ideal physical quality in a soil that determines healthy chemical and biology activity. First dig a hole and lift out a large chunk of soil. If there’s a good amount of organic matter, then the smaller bits of soil (aggregates) will be knitted together by humus (organic matter). Each aggregate will feel crumbly and will shatter easily when squeezed, indicating a friable soil. On soil with good drainage, heavy rain and surface water will drain away within a few hours, but moisture will be absorbed by soil particles (water-holding capacity) for plants to use later. Also, in dry weather and after cultivation, a well-structured soil will hold together and not get eroded by the wind.
Plant observation: Other than a soil test, the best way to determine whether a soil has the right chemistry is by observing how well your crops grOw. If the soil is poor in nutrients, plant leaves will show discolouration and won’t grow to full size. There are also some weeds that indicate healthy soil: chickweed, chicory, fathen, redroot and groundsel.
Biological indicators: First, smell the soil. A fertile soil smells musty/earthy, almost sweet, indicating good numbers of actinomycetes (important soil micro-organisms). A sour-smelling soil indicates lack of air, and is acidic. Colour indicates how well organic matter is being incorporated into the soil. Generally the healthier the soil, the darker it becomes. Lastly is the earthworm population. Dig a spade-sized hole (20cmx20cm) and count the earthworms. A healthy soil should have at least 25 worms (that’s 500 worms/m2), while a healthy pasture could have 80 per hole (2000 worms/m2).
Hopefully you have healthy garden soil. If not, then there’s plenty of ways to improve it and grow great crops.
Fruit care
Plant fruit trees/shrubs. Stake and tie (bicycle innertubes are great!). Protect from wind and animals.
Complete pruning of pipfruit (apples, pears etc) and berryfruits.
Sow understorey plants under fruit trees or on edges to encourage beneficial insects and improve soil health (Kings Seeds have mixes).
Mulch fruits with woody compost, and manures (especially citrus and peaches).
Prepare new strawberry beds. Add compost, leaf mould and mulch with pine needles.
Prune citrus when harvesting. Frost protect young plants. Spray citrus with all-purpose oil for scale insect. Mulch with manure and woody compost.
Divide rhubarb.
Spray everything with diluted seaweed solution. Copper spray stone fruit vs brown rot, or pipfruit vs black spot. Spray lime sulphur on fruit trees vs peach leaf curl, black spot, powdery mildew, scale, mites and borers.
Herb care
Transplant rooted cuttings from last year.
Weed herb beds in preparation for sowing annual herbs, like parsley.
Sow herb seed.
Vegetable care
Plan next year’s crops. Buy seeds and set up propagation for main spring sowing end August-September.
Dig in green manures or cut and cover with black plastic for mid-spring plantings.
Plant early potatoes into organic-matter-rich soil and protect from frost.
Prepare beds for hot crops (tomatoes, cucumbers, etc). Add lots of compost, blood and bone, organic compound NZ fertiliser.
Prepare seedbed for upcoming sowings of root crops.
Plant asparagus: dig a deep trench (up to 60cm deep). Add animal bones in trench for long-term calcium supply. Add lots of rich organic material and make sure there are no weeds like couch. Add sand if your soil is heavy. Keep turning compost.
Continue planting brassicas into fertile beds. Add blood and bone as a supplement.
Sow/plant salads under cover (cloche or plastic bottles) and winter greens for ongoing supply.
Sow/plant beneficial flowers, eg phacelia.
Hothouse: Clean for better light and look for hibernating snails. Prepare soil for heavy-feeding fruiting crops. Tidy propagation gear and organise seed-raising mix. Make indoor compost to raise temperature.
For transplanting: All seeds 23 August. Leafy greens (spinach, spinach beet, silverbeet/chard, lettuce, endive, and cabbages)(best 6th August). White and red onions (best 13-15 August). Broccoli, cauliflower. Flowers, eg marigolds.
Sow direct: All seeds 23 August. Mesclun salad, spring onions. Peas (cover). Radish, carrots, beetroot (cover), turnips, swede (Best 13–15 August). Flowers, eg cornflower.
Plant: Salad greens, spinach, broccoli, cauliflower, cabbages and Chinese cabbage. Early potatoes in frost-free areas. Flowers, eg everlasting daisy seedlings.
General garden care
Fix and clean garden tools.
Lime the lawn.
Take a soil test for garden and orchard areas (try www.hillslaboratories) and organise minerals to offset deficiencies.
Prune for light and tree shape and shred prunings.
Collect seaweed/seagrass.
Sol Morgan, GroWise Consultancy
