Blossom end rot

A common problem affecting otherwise healthy tomato and capsicum plants during heat waves is blossom end rot, where partly formed fruit develops a dark, sunken patch furthest from the stem.
This is caused by calcium deficiency, and is not a disease. Like us, plants need a good supply of calcium to form a strong structure. Hot and very windy days increase transpiration (water loss) from plants in the same way we perspire to keep cool, and calcium can only be absorbed by plants as water-soluble, electrically-charged ions. This problem can also affect zucchini, pumpkin and melon plants.

During heat waves, daily watering rarely solves the problem. A deep watering a couple of times a week is more beneficial. If soil around plants is mulched to keep roots cooler and reduce water loss, an efficient way to water quickly is to place juice or soft drink bottles, neck down, beside plants. See: Watering in drought conditions

Other causes of blossom end rot are:

• Erratic watering
• Soil is too acidic (soil pH less than 6)
• Poor fertilising routine
• Overuse of fertilisers high in nitrogen or potassium, including some seaweed fertilisers
• Rarely, in very alkaline soil where calcium becomes insoluble.

Winter tomatoes

  There is nothing like the taste of vine-ripened tomatoes, and this is how my neighbour, Cheryl, keeps her tomatoes cropping through winter on the Mid-North Coast of NSW. The tomato plants self-seeded in the rose garden in front of her north-facing verandah and, as they grew, she trailed the foliage across the verandah surface. The plants get plenty of sun during the day and the verandah roof keeps the plants warmer at night and protects them from frost. This clever idea has worked very well and Cheryl has so many tomatoes, she has been giving them away.

Tomatoes can also do well during the colder months in pots on a protected north-facing verandah, as the potting mix in black plastic pots stays warmer than soil in garden beds. Fruiting on tomatoes depends on warm air and tomatoes do not need bees for pollination. Don’t forget to water the plants regularly, and give them a light application of complete organic fertiliser as flowers start to form, to ensure a sweet-tasting crop.

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

Aubergine (eggplant)

eggplantwht Have you ever wondered why they were called eggplants? This variety is the reason. The small white fruit, which look like hens’ eggs hanging on a bush, has a delicious flavour but has been very difficult to find in recent years and I was delighted to finally find some seeds. Yates has ‘White Star’ and there is a variety called ‘Easter Egg’ available from an Australian grower on eBay.

Aubergines (Solanum melangena) are a member of the tomato family and require a similar position, soil preparation, and soil pH. However, they require warmer conditions for germination than tomatoes and are usually sown 1 cm deep in small pots in a warm, protected position. The small, white variety produces a compact bush and can be grown in beds or pots. Aubergines need staking because the stems are brittle, and they appreciate a light application of poultry-based, complete fertiliser as buds form. Regular harvesting increases production. Cut fruit from the plant with a 2 cm stem when the skin is firm and shiny.

Healthy tomatoes

tmtroots A strong, healthy root system that allows your tomato plants to absorb enough water and nutrients is essential for producing a good crop and allowing your plants to produce their own pest-deterrents. Tomatoes in their natural state, grow along the ground and will form auxiliary roots along their stems, but our method of growing tomatoes tied to stakes prevents this.
However, you can give them a helping hand to produce extra roots before planting out by lying potted seedlings on their side when they are 10-15 cm tall. Leave them like this for a week or so, depending on the growth rate, and remember to stand them upright for watering. As you can see in the photo, the main stem with make a 90-degree turn, and root buds will form on the horizontal part of the stem. Plant them out with the growth tip vertical and the horizontal stem just below the soil surface. Or, you can remove the seed leaves and plant them up to just below the next set of leaves, then hill soil around them slightly as they grow.

French beans

OLYMPUS DIGITAL CAMERA Occasionally, garden gurus will say that “beans will grow on the smell of an empty fertiliser bag because they will fix nitrogen in the soil”. This is not true in Australia, where the soil bacteria that is necessary for these legumes to fix nitrogen does not occur naturally. Gardeners are often then disappointed to find that the lower leaves of their beans and peas have yellowed.
French or green beans (and peas) will benefit from the addition of some mature compost and a light application of complete fertiliser when preparing the planting area. Plants need more than nitrogen to be healthy and produce good crops, and compost in soil helps beans resist bean fly.
French beans do well in a sunny position with a soil pH not lower than 6. However, they may need some temporary shade during our heat wave conditions. Regular, deep watering and a 5 cm layer of mulch over the bed will help to keep them growing strongly. Bush varieties of French beans grow best when sown in a block rather than rows, and can be ready to harvest in eight to ten weeks after sowing.
For a continuous supply, sow a small quantity each month listed in the monthly planting guide for your climate.

Moving trees and shrubs

Sometimes it is necessary to move an established tree or shrub. Deciduous plants can be moved in winter or early spring, and evergreen plants in spring. This is best done in two stages if you have to move an evergreen plant, but sometimes situations arise, due to weather conditions or moving house where a shrub or tree has to be moved urgently.
This advice is for moving trees and shrubs small enough not to require the assistance of mechanical equipment.
dripline1

  1. Dig a deep trench around the plant you want to move, using a sharp spade to cut through the roots. The trench will usually have to be dug inside the drip-line of the plant, otherwise the root ball will be too large to handle. The drip-line is the area of soil directly below the outer edges of the foliage – where rain runs off the leaf canopy onto the soil. This is where the feeder roots usually lie.
  2. Water the area thoroughly, but do not apply fertiliser. Then prune back the foliage, or remove whole branches in the case of frangipani. This is necessary to compensate for a smaller root ball, so that the plant will not suffer water stress.
  3. If possible, leave evergreen plants in position for about a month, watering it regularly. This will help the plant to produce some feeder roots within the reduced root ball area.
  4. When ready to move the plant, make sure the soil is damp. Get a large piece of hessian, shadecloth or weed mat and some cord. This will help to keep the root ball intact during transplanting. A trolley, or tarpaulin or another large piece of strong fabric will help to use as a sled to drag the plant to its new planting position if the plant is too large to lift into a barrow.
  5. First dig the hole where the plant is to be positioned. Fill the hole with water. This is important for two reasons. How quickly the hole drains indicates whether drainage is good or you will need to plant the tree or shrub in a raised mound. If the surrounding soil is not damp when you transplant, the water you apply after planting will be drawn away from the root ball into the surrounding dry soil, and the plant will look stressed several days after planting.
  6. Work the spade around the trench dug previously, easing the spade further and further under the root ball until you have cut through all the roots.
  7. Place a clear mark on the north-facing side of the plant so that it will be positioned in the same orientation.
  8. Ease the fabric gently under the root ball. It will be much easier if someone helps by slowly tilting the plant to one side. Gather the fabric around the root ball and tie with cord.
  9. Carefully transfer the plant to the new hole positioning it at the same level it was planted previously. Untie the fabric and gently ease it out from under the root ball.
  10. Fill the hole with soil, adding some compost, if available. Do not trample the soil around the plant. Water thoroughly to remove any air pockets around the roots, and apply a 5 cm layer of mulch around the plant, keeping it a hand span from the trunk. Job done.

Staking a replanted tree or shrub will stabilise it until it becomes established in its new position. Gardening Australia has an excellent video on how to support plants using 3 stakes. See: 3 stake method

** Please note: Moving Eucalyptus taller than 45 cm, or other plants that have tap roots is often unsuccessful.

Cloche for seedlings update

cloche With very cold weather set to continue over much of Australia for some time, gardeners can protect young seedlings with an easy-to-make cloche. This simple structure named for the French word for ‘bell’ keeps plants warm on chilly nights and can be easily ventilated so that they don’t get too warm during the day. When the nights are milder, the structure can be easily folded and stored until it is needed again.

Instructions for making cloches can be found here: Cloche for seedlings.
** And remember to leave frost-damaged parts on shrubs until all risk of frost has passed. They may look unattractive but the burnt portions are protecting the plants from further damage.

Pruning tub plants

mandarin.jpg Citrus, dwarf fruit trees and many ornamentals grow well in large tubs. However, there comes a time when the plant is growing in the largest pot size and needs pruning to remain in the tub or pot.

To keep these plants healthy, ease the root ball out of the tub and, using a sharp knife, cut a straight line through opposite sides of the root ball – 8 cm in from the edge of the widest part of the root ball, as shown in the diagram. Trimrootball The space provided by the reduced root ball and the amount of potting mix that falls away from the root ball will allow space for enough fresh potting mix to be added to the tub. After checking that the drainage holes in the base of the tub are clear, replace the plant in the pot with fresh organic potting mix.
Trimming plants in this manner provides space in pots without damaging all the delicate feeder roots. Place a durable plant tag into the top of the fresh mix on one of the sides where it was trimmed. When you need to re-pot the plant again, make the pruning cuts at right angles to the previous cuts.

Tip pruning the foliage will compensate for the temporary loss of roots and prevent the plant becoming straggly.