Spacing, watering and useful weeds
Improve the soil
Perth sand is ancient and has little to no nutrients in it. Sand as a soil medium is hard to improve but it can be done. The addition of clays, minerals and manures as well as using a good potting mix or soil conditioner when planting will make a huge difference to your garden’s health. It will make the soil softer and allow water to soak in more deeply. If non-wetting occurs it can be remedied by incorporating organic matter, such as mushroom compost, old straw or green manure into the soil before planting.
Make a bowl shape, or berm, under the plant’s dripline, to catch and hold moisture, leaves and other detritus, which helps feed and protect the soil. Once the ground has been thoroughly wet once it should be easier to soak again next time.
Leave room for plants to grow
Always leave room for plants to grow into. It can be tempting to fill a space with small seedlings or other young plants but as they grow larger overcrowding can impede growth.
Valuable or slow growing trees can benefit, however, from what is known as a nurse plant, a faster-growing hardy species placed to protect the more valuable tree from prevailing weather such as drying winds or salty air, or to fix nitrogen and provide shade. The nurse plant provides protection for the young plant, creates a better microclimate and allows the tree to establish before its nurse plant is removed.
The root zone is also important to consider, as some large trees have extensive root systems, which can damage wall foundations or simply out-compete any other plantings for light, water and nutrients.
Keep note of what, when and where you plant seeds, especially if you want to collect seed later and will need to know what varieties you’ve planted. Progressive sowing is also a good habit to get into. Repeat sowing some of your favourite and most commonly used vegetables, such as spring onions, carrots, lettuce or whatever you eat most of will provide an ongoing supply. Beans can be sown again when the previous seedlings start to flower.
Trickle systems are the most efficient way of watering, providing the drippers are checked frequently and the filters cleaned. Wicking beds or self watering pots are also proving to be quite a useful method of growing in Perth and other dry climates.
A lot of household water can be reused, reducing your water bill and allowing grey water to help keep your garden alive. Grey water can be used on non-edible parts of a garden and fruit trees will be happy for it. Compost can benefit from fine food particles in washing up water, and even a bit of detergent isn’t too bad, as long as it’s not too strong.
Planting things with similar water needs together is important. Many commonly grown leafy food plants need lots of water, while the smelly Mediterranean herbs such as rosemary, sage and lavender actually grow better with less water, their aromatic oils being stronger in drier areas.
Water DEEPLY and INFREQUENTLY
Many plants that are adapted to dry conditions and perennials with a deep root system prefer to be watered deeply to encourage roots to delve down. Many plants can show signs of serious water stress in early summer, especially after a dry winter when the plants wilt and the leaves curl. This may be mistaken for a fungal disease. If watering then occurs it may be too late, and the plants stressed system collapses.
A weed is any plant in the ‘wrong place’. This means any plant, from tiny annuals to huge trees. A 20 year-old lemon-scented gum is a weed in Perth’s native bush land, but gorgeous in the right big back yard. Some folk consider all non-native plants as weedy. The job weeds do is very important when it comes to protecting and improving degraded or bare soil. In many cases, the weedy species are the only thing that will survive in those areas, but then a human comes along, pulls the weeds out and wonders why the area won’t support any life! In some cases, it may be better to leave them in the ground, to protect the soil from blasting sunshine, prevent soil erosion and to provide some retreat for soil life.
Many tap-rooted flat weeds, such as dandelion, cape weed and cats’ paw bring nutrients up from the subsoil, to deposit them on the surface. I have seen the soil underneath dandelions teeming with worms at the end of summer. They are constantly building up the soil, and after three years the roots are good for harvesting. Other common leafy weeds including dandelion, sow thistle (NZ’s ‘puha’), amaranth and nettle, for instance, are really good food. Many are high in minerals and vitamin A. Just be sure not to pick them near busy roads or popular dog-walking areas.
Nearly pumpkin time again: The Cucumber Family
Many fungal problems are caused by overcrowding or lack of air flow. This is seen on cucumbers, pumpkin, squash and zucchini, which easily get powdery mildew.
- Plant them into a well enriched soil with plenty of room and lots of sun. When planting the seed or seedlings of the cucumber and pumpkin family, put in a stake next to it so you know exactly where to water.
- Water in the morning only! Extra humidity at night will only encourage fungal problems.
- Liquid seaweed concentrate is a great booster to apply to the pumpkin family. One of the few times you should wet the leaves is when watering with seaweed products. There are minerals in seaweed that protect the leaf from fungal attack. It is useful for all other types of plants, too. The seaweed may help prevent the fungus growing if you spray before the leaves are affected.
- Remove the worst affected leaves as they get older. Do not put them in your compost.