Heat wave help

recycled juice bottle

 

With high temperatures predicted for many areas of mainland Australia this week, I would like to remind you that you can find tips on helping your garden to survive extremely hot temperatures here: Heat wave protection

Watering in drought conditions

This week, two readers have asked me about garden problems caused by lack of water. As you know, it is extremely difficult to keep gardens well-watered in drought conditions. However, as plants can only absorb the nutrients they need for healthy growth and ripeness of crops as water-soluble ions, inadequate water is the cause of a wide range of problems, including pest attack.

Bare soil in garden beds and around trees, shrubs and vines allows a lot of soil moisture to be lost to evaporation. A 5 cm layer of organic mulch over beds and around larger plants (keeping it a hand span from the trunk) will prevent water applied to the soil from being wasted. Lawns are greedy and as their roots are close to the soil surface, they take water and nutrients intended for fruit trees and favourite ornamentals. Keep lawns beyond the outer canopy of trees and cover the area under trees with mulch.

wtrbttle.jpg A method that we have found very helpful to water mulched beds is to use plastic soft drink and juice bottles to funnel water through mulch directly to the root area of susceptible plants. This is a quick and very efficient way to hand water during drought, water restrictions, heat waves or windy weather. Limp tomato seedlings will freshen up in about 10 minutes after watering by this method.
Simply cut off the base of each container, remove the lids and bury the necks of the containers about 8 cm deep near outer edge of the foliage of plants. Large shrubs may require several containers. Pour water into the container until it begins to drain slowly – an indication that you have dampened the soil in the root area.

Seedlings and pot plants are usually the first to suffer during heat waves, and you can find advice on how to revive stressed pot plants here: Pot plant stress

Windy weather update

Transpiratiion Predictions are for more cold, windy weather on the way. Keep a close watch on your garden as wind can dry out soils faster than summer heat, resulting in cell collapse of soft tissue plants. To discover why this happens and how to protect your plants, see: Windy weather
Seedlings and many vegetable crops are vulnerable to wind damage in winter and early spring. Ripening citrus are also easily damaged by strong winds.

Heat wave protection

Some parts of Australia are enduring extremely hot weather and, apparently, there is more to come this summer. Periods of intense heat can cause scorching in many gardens.
Although European-based garden texts recommend full sun for most vegetables, where summers are hot and air pollution is low, full sun can result in sunscald. While Australian natives have evolved to restrict loss of water through leaves in hot, dry conditions, very hot plants, especially those that originated in cooler Northern Hemisphere regions – such as most of our vegetables and fruits, lose a lot of water through their leaves in an effort to keep cool, in a similar way to humans perspiring.

A bit of shade
shdeclth Providing some light shade during the hottest part of the day can prevent sunscald on susceptible crops, and, by keeping the plants cooler, reduces their water consumption, an important consideration where water restrictions apply. We use lightweight, knitted shade cloth, supported by arches made from 38 mm irrigation pipe attached to garden stakes or star stakes, or you can use old light-weight curtains or sheets.
Each canopy is positioned to allow morning sun to reach plants, yet not restrict air flow around them. Poor air flow (such as in fully enclosed areas) can produce conditions suitable for some fungal diseases to establish. Instructions for making these can be found in the post Sun and heat protection.
However, in an emergency, any old curtains or pieces of lightweight fabric will do. Tie the corners to garden stakes to provide some relief for garden beds during the hottest part of the day.
If possible, move potted plants to a shaded area of the garden, and group them together. This provides more humidity around the plants, and reduces their water requirements.

Water is essential
wtrbttle.jpg Adequate soil moisture is essential for your vegetable garden to maintain good growth during heat waves. Mulching garden beds is very helpful. A method that we have found very helpful to water mulched beds is to use plastic soft drink and juice bottles to funnel water directly to the root area of susceptible plants. This is a quick and very efficient way to hand water during water restrictions, heat waves or windy weather. Limp tomato seedlings will freshen up in about 10 minutes after watering by this method.
Simply cut off the base of each container, remove the lids and bury the necks of the containers about 8 cm deep near outer edge of the foliage of plants. Large shrubs may require several containers. Pour water into the container until it begins to drain slowly – an indication that you have dampened the soil in the root area.
Seedlings and pot plants are usually the first to suffer during heat waves, and you can find advice on how to revive stressed pot plants here: Pot plant stress

Water for wildlife
Birdbath Don’t forget to provide water for birds and bees that visit your garden. A bird bath, or containers of clean water positioned where cats and dogs can’t reach them will provide relief for the insect-eating birds and the bees that pollinate your crops. Chlorinated pool water is toxic to these helpful creatures. A container of water under shaded foliage will be appreciated by your resident frogs too.

Pot plant stress

Forecasters are warning of more hot days to come. During heat waves, pot plants become stressed more quickly than plants in garden beds, and your pot plants may not getting as much water as you think.
If potting mix dries out, the first sign may be complete collapse of a plant. If you water dry potting mix in the normal way with a hose or watering can, your plants may not be getting as much water as you think. This is because potting mix shrinks slightly when it dries, leaving a narrow gap between the mix and the pot. When you water, most of it runs into the gap and out through the drainage holes, leaving the mix around the roots still dry. Seedling punnets and smaller pots can be thoroughly watered by immersing the entire pot in a bucket half filled with water, or use a laundry tub if a lot of pots need reviving.
Water should come over the top of the pot. Leave the pot in the water until bubbles cease to rise. Short term immersion won’t hurt the plants. Then lift the pot allowing it to drain into the bucket or tub. This method of watering also works very well when your water supply for plants is strictly limited.
For pots too large to be immersed in a container, fill some large soft drink or juice containers and insert 2 or 3 neck down into the potting mix. Provide support if necessary and allow them to empty slowly into the mix. Re-fill the bottles and repeat watering until water is being drawn into the mix very slowly. If heat is likely to continue for some time, place some mulch or stones on the surface of the potting mix to slow evaporation.
Potting mix can become incredibly hot when pots are in full sun. During extreme heat conditions move pot plants to a cooler spot, including under trees. Grouping them together helps retain humidity around the plants and reduces water loss through the leaves.

Worm farming

HOMEMADE WORM FARM
compworms.jpg My husband has been busy with his chain saw carpentry again. He rescued a shower base bathtub from the local tip to make a small worm farm that could be set up in a shady spot near the house. This makes it easier for me to collect worm castings for my seedlings and pot plants. Worm farms are a wonderful way to recycle food scraps and household waste into fabulous 100 % organic complete fertiliser with a neutral pH.
Old bathtubs are hard to come by in our area, as they are popular for recycling as water troughs for horses. However, this tub was missing the plug rim and unsuitable for use as a water trough, so it was a lucky find.
Using his trusty chain saw, Brian built a simple frame for the tub, using scrap hard wood pieces from around the farm. The cover consists of recycled hardwood planks, placed side by side, across the top of the farm. Only the two end planks are attached to the frame. The loose planks allow me to expose as much, or as little, of the worm farm surface as I want when adding food or collecting castings. A large square of fly screen was placed across the base of the tub before filling to prevent the worms and castings falling through the drainage hole. A bucket is positioned under the drainage hole of the tub to catch the liquid that drains from the worm farm.

chnsaw.jpg wormfarm.jpg

A layer of edible bedding is needed across the bottom of the farm container for to keep the worms damp and protect them from temperature fluctuations. I added some of the digested matter from our main worm farm for bedding as this contained both worms and worm eggs to ensure that numbers in the new worm farm will build up more quickly. However, for new worm farmers, bedding can be shredded and soaked coconut husk fibre (Coco peat), or damp, aged cow or horse manure, and the starter worms are placed over the bedding where you want them to feed. I added some chopped scraps (in a 2-cm layer) to one half of the surface of the farm, so that the worms would be concentrated in that area. The surface of the farm was then covered with wet newspaper and the cover planks over the top of the farm. (A temporary plastic cover goes on when heavy rain is predicted.) Food is replaced as often as necessary. If your worm farm is new, don’t give them too much food at first or it will be a while before they eat all the food, and it will start to smell. But, if you don’t give your worms enough to eat, their growth and reproduction will be slow.

As worm numbers increase, they will be able to process larger quantities of waste. Once the worms have turned the food and bedding in their area into castings, I start putting food at the other end of the farm. This allows me to collect castings more easily from the other half and pour water through the processed bedding to collect some liquid for my plants. It is not recommended to pour water through undigested food in worm farms in case the food has been affected by fungal or bacterial disease. However, using common sense and following the organic principle of “feed the soil, not the plant”, avoids problems with liquid fertilisers.

When to water?

A common question asked by gardeners is how often should they water their garden.
Unfortunately, limited watering times imposed by water restrictions have encouraged some gardeners to rush around giving everything a light watering during the allocated time.
A light daily watering is one of the worst things you can do for your garden. It only encourages plant roots to stay close to the soil surface – the area that dries out first.
Plants watered in this way wilt quickly on hot, or windy, days – encouraging gardeners to perpetuate the cycle.
If you use mulch, very few plants need watering every day. Mulch not only prevents water loss through evaporation from the soil surface, it assists the capillary movement of water through soil. Seedlings will probably require daily watering through the warmer months because they have very small roots systems.
The most reliable way to decide if plants need watering, is to poke a finger, up to the first joint, into the soil or potting mix. If the soil feels damp, the plants don’t need watering. If the top centimetre or so feels dry, give the plants a thorough watering, under the mulch. When watering shrubs and trees, water under the outer edges of the mulch where the feeder roots lie, not near the trunk. Plants watered in this way develop stronger root systems, and will be more resistant to adverse climate conditions.
Many plants slow their growth or become dormant in winter, and they need less watering than in warmer months. More pot plants are killed by over-watering, than under-watering. When the surface of potting mixes feel dry, small pot plants can be watered, at any time, with water collected while waiting for the shower to warm, as long as you remove the bucket before getting in the shower and making the water soapy. Dunk the pots into the bucket until bubbles cease to rise from the water surface. Overhead watering of indoor plants can encourage fungal diseases, especially in the cooler months.