It’s finally time to breathe in the cool, damp air of late autumn and enjoy the changing seasons as summer slips into winter, as we explore what to include in your May garden calendar
Cool & Temperate
Brassicas, including kale, cabbage, broccoli and Brussels sprouts, are magnets for cabbage white butterflies and their larvae. They can destroy entire crops. Regularly inspect the leaves and stems for these very hungry green caterpillars and squash any you spot along with their eggs, which may be found under the leaves. The best way to stop this caterpillar invasion is to drape fine white mesh over the crop. Keep it off the foliage with stakes to create a mini shade house effect. Lift the cover to water and fertilise the plants, then put it back.
In cool and inland areas, it’s time to be on frost alert. These icy reminders of winter are likely to begin this month. Frosts bring an end to pumpkin vines, sweet potatoes and even choko vines, but help clear up pests and weeds. Clear away frost-damaged annual vegies. Harvest any vegies that remain on vines and stems. The cleared space can be used for late winter and spring crops.
Sow seeds of kale and other brassicas along with cool-season legumes such as peas and snow peas.
Prepare to protect subtropical fruit trees (such as lemons and other citrus, avocados and mangoes) in cold, frost-prone areas. Even where frosts are not common, cold winter winds can damage these sensitive plants. Move any that are in containers into shelter to protect from frost and cold winter conditions. Warmer spots include a greenhouse, covered patio or against a north-facing masonry wall. Where the trees are growing in the garden, protect them in situ with a screen to cut out cold winds and cover other frost-susceptible plants such as mangoes and any small trees under around 1m high. Grafted trees are particularly vulnerable to cold, especially young trees. To protect the graft area on a trunk, wrap the graft area with hessian or corrugated cardboard through winter.
Deciduous fruit trees such as plum, cherry and peach trees survive the winter chills by entering dormancy so don’t need winter protection. This means they can be planted now and in the months ahead as bare-rooted plants.
Compost & Soil
Continue to rake and pile up the season’s bounty of fallen leaves. Add them to compost and leaf bins. For fast and efficient work use a wide, tyned rake to cover a larger area with each rake. Dry leaves are hard to control. The easiest way to move them is to rake them onto a large drop sheet or tarp, which can be dragged to the compost or leaf bin. Alternatively, make leaf mould in large sacks or bin bags. Make sure you use any of last year’s leaf mould that’s still around. Leaf mould is ideal to dig in to prepare the soil for new plantings or to cover winter-bare soil before spring plantings. This nutritious mulch can also be spread around fruiting trees or used as mulch around annuals or on top of potted plants.
While decomposition may slow down in compost heaps over winter, a cold winter can kill the worms in a worm farm. In the ground, worms and other creatures can burrow more deeply to avoid cold conditions. To keep worm farms warm, move them into a sheltered spot and cover them with hessian. The rate at which the worms consume scraps may also decrease, so add materials in smaller amounts. Chopping scraps into small pieces or giving them a quick whizz in a blender can help worms digest more material faster.
As the weather dries and humidity drops during the dry season, it’s important to increase watering, especially of raised garden beds, which drain quickly and so dry out fast, too. These dry and mild conditions of late autumn provide ideal growing conditions for a wide range of traditional vegetables that don’t grow so well in the wet season when the conditions are so hot and humid. This is the time to get planting and sowing seeds for the months ahead!
Legumes including snake and winged beans along with broad beans and peas can go in, along with salad vegetables such as tomato, cucumber, leafy greens and herbs. Also plant another crop of sweet corn. In tropical zones, continue to plant and grow zucchini and pumpkin through the dry season. Provide regular deep watering and keep weeds under control until the leafy growth can form a natural ground cover.
Fruit trees provide shade as well as fruit, making them a good addition to tropical gardens, but where space is a premium look for smaller-growing shrubby and dwarf trees. These are also easier to cover to protect from pests. Custard apples and dwarf avocados are good small fruit options. Don’t be put off by the look of the outside of these custard apples. The exterior may be lumpy and green in appearance but the creamy flesh inside is always delicious — just spit out the brown seeds. Some custard apples take many years to produce any fruit — even named, grafted varieties — so patience and often hand pollination are required to get a crop. Some trees also need cross-pollination to fruit well. For a fast-cropping compact plant, look out for ‘Tropic Sun’, which is more reliably self-fertile than older varieties but has fewer seeds. To keep custard apple trees growing well, apply a little slow-release organic fertiliser each season.
Compost & Soil
To improve soil fertility and restore nutrients lost to leaching over summer, sprinkle blood and bone or other organic fertiliser over the soil before planting. Before replenishing mulches, water the soil well, then spread a layer of compost or well-rotted manure. Finish with a layer of coarse mulch such as composted bark to about 5cm depth. Soil, particularly sandy soil, under a thick layer of mulch can become water-repellant but a thin layer of coarse mulch deters weeds and keeps soil cool without blocking out water or causing water repellence.
Regularly check mulches for signs of termite activity, which includes mudding and tubes where the termites can travel from their nest to the food source without drying out. Where areas are not being cultivated over the dry season, keep them weed-free with mulch or by sowing a green manure crop that can be dug into the soil ahead of planting in spring.
Written by Jennifer Stackhouse
Originally in Good Organic Gardening magazine Volume 9 Issue 1