Windy weather

Transpiration Garden beds dry out very quickly in windy weather, including those beds protected by mulch. The reason is that plants maintain some humidity around them by drawing water from the soil and releasing it through tiny holes in their leaves, a process known as transpiration. As strong wind constantly removes the moisture, more and more water is drawn from the soil in an effort to maintain humidity. As soil dries out, cells collapse in the soft tissues of plants causing drooping of plants and possibly death of small seedlings.
A way to avoid this problem in windy weather 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 or windy weather. Limp tomato seedlings will freshen up in about 10 minutes after watering by this method.

wtrbttle.jpg 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.

For plants that are generally sensitive to wind, filtering the wind rather than blocking it provides better protection for delicate plants. A solid cover or wall causes wind to whirl around on both sides of the screen, but a lattice trellis or product called ‘Windbreak’ on the side of the prevailing wind reduces the impact of the wind, as indicated below.
windbreak

Seeds that need light

OLYMPUS DIGITAL CAMERAMost seeds germinate in dark, damp conditions and need to be covered with a suitable depth of topsoil. However, some seeds need light for successful germination.
In the vegetable patch, only varieties of lettuce, Cape Gooseberry, Tomatillo and the Asian greens Seakale and Shiso are ‘light responsive’, but a number of herb and flower species also require light for germination. These include: Angelica, Anise, Arnica, Ashwaganda, Caraway, Catnip, Chamomile, Chervil, Dill, Echinacea, Elecampagne, Evening primrose, Feverfew, Gazania, Lady’s Mantle, Lemon Balm, Mignonette, Rosemary, Summer and Winter Savory, Valerian, Watercress, Wormwood and Yarrow.
Sowing seed for these plants can cause difficulties as the seed is merely pressed into the soil surface and require close attention to prevent them drying, resulting in germination failure. Or, they are scattered on the surface of a punnet where they can be easily washed into clumps at the edge of the punnet despite careful watering.

A way to avoid problems with these seeds is to fill a punnet with damp seedling mix and then cover the surface of the punnet with a single layer of gravel or small pebbles. Then sprinkle the seeds sparingly over the gravel and water very gently, being careful not to flood the surface. The gravel provides crevices for the seed to settle while still allowing them to receive light, and also helps to keep the growing mix damp for germinating seeds.

Passionfruit – hand pollination

Passionfruit vines rely on bees to pollinate their flowers because they have a large gap between the pollen-bearing male parts of the flower and the female part. Only when the female part of each flower receives passionfruit pollen can the flower form a fruit. If you don’t have a lot of bees around your passionfruit vine, or if you have a young vine with few flowers, you can pollinate the flowers by hand.

All you need is a small, soft watercolour paintbrush for the job, and this short video by “woodyfriendron” demonstrates the practice beautifully:

http://www.youtube.com/watch?v=eicamZk1qis

Pumpkin problems

Karen has had disappointing results from her Queensland Blue pumpkin vine which produced pumpkins with very little flesh and she wants to know how to avoid problems in future.

Karen, if the seeds are soft and immature, you may have picked the pumpkins before the ‘fruit’ has fully developed, and pumpkins are fruits although we call them vegetables. However, if the seeds are mature, a common cause of this problem is hunger, and this can occur in several different ways even though you may have thought that the plant was well fertilised.

If soil is not damp, nutrients can’t be absorbed by the roots. If soil pH is too acidic or alkaline plants will go hungry because the soil pH controls which nutrients are available to plants, and pumpkins need a soil pH of 5.5-7 for good growth. Pumpkins vines can produce an enormous amount of foliage – and it is a huge task for the roots at the base of the vine to provide moisture and nutrients through the whole plant. When pumpkin vines are allowed to wander over soft earth, they will usually put down extra roots along the vines to assist with water and nutrient absorption.

You can encourage the formation of extra roots, see Assisting root growth.

Pumpkin flowers are pollinated by bees and occasionally a flower or flowers can be pollinated by pollen from a cattle pumpkin, which usually results in fruits that are tough and pretty tasteless. (If your neighbours are growing cattle pumpkins, you may have to hand-pollinate pumpkin flowers).

I’d advise you not to save any seeds from pumpkins that have little flesh or tough flesh as any vines grown from these seeds will probably produce poor quality crops. Only use seed from your best home produce or purchase seeds from a reputable supplier.

Pumpkins thrive on compost, so make compost through the winter ready for next season’s vines. Turning the heap a couple of times a week will keep you warm, keep the heap aerated, and speed up the composting process. If you live in a cool climate, put some black plastic over the top of the heap to help absorb heat. Use the compost to get your pumpkin vine off to a flying start in a different spot in your garden when soil warms in spring.

Growing potatoes update

A reader has asked if potatoes can be grown in the plastic tubs that are sold by Bunnings, Big W, etc., and I will answer it here as the links may be helpful to other readers.
Yes, Rebecca, they would be suitable if you add plenty of drainage holes and put several centimetres of gravel in the base of the tubs so that the potting mix does not block the drainage holes.
Opaque tubs provide similar conditions to small or medium drums (in that the young plants will be more shaded) and you should use those instructions for the tubs in this post. Basically the seed potatoes need at least 15-20 cm of potting mix underneath them and 15 cm of mix above them. Seed potatoes should be sown/planted 30 cm apart and, if they are the tubs I’m thinking of, you would probably only get one plant per tub as there is not really enough room for tubers of 2 plants to form.
The how and why of ‘hilling-up’ potato plants can be found in this post: Growing potatoes.

Advice on suitable soil conditions for the best results from potatoes can be found in Potato beds.
Also see: Other ways to grow potatoes.

Spinach

English spinach is an annual that loves cold weather. It is a fast growing, small plant that forms a rosette of green leaves and stems with a flavour more delicate than that of silverbeet.
It is a versatile vegetable that can be steamed or used in pies, quiches and soups, and is rich in folate, vitamins A, B6, C and E, as well as magnesium, iron and fibre.
In well-drained soil containing plenty of compost and a scattering of organic complete fertiliser, spinach plants are ready to harvest in 8 weeks. Sow seeds in pairs, 1 cm deep and 25 cm apart, directly where they are to grow, and seedlings should appear in 7 days. About a dozen plants are enough for the average family. Keep seedlings well-watered and give them a drink of half strength manure tea or organic liquid fertiliser about a fortnight apart until plants are well established.
When seedlings are about 5 cm tall, remove the weakest seedling of each pair, and use the well-washed thinnings in salads or soups. Where winters are long, progressive sowings can be made each month through winter. Don’t worry about sowing too many plants as English spinach freezes well. Blanch the washed leaves, pack them into ice cube trays with a little water, and freeze. Then transfer frozen cubes into a ziplock plastic bag for storage in the freezer.

This spinach is ‘Galilee’, a variant developed in the Middle East that is a lighter green and more tolerant of warmer winter temperatures – seeds available from Green Harvest.

Planting spring bulbs

The autumn equinox (when day and night are of equal length) occurred on Tuesday, March 20th, this year. Days are becoming shorter than nights now, and it is time to prepare soil for planting spring-flowering bulbs. These plants thrive in a compost-rich soil with some complete organic complete fertiliser added. Gardeners in Cool climates and New Zealand can plant bulbs now. However, as these bulbs grow better after a period of chilling, gardeners in warmer areas can put bulbs into the vegetable crisper of the fridge for about a month before planting.
Bulbs are normally planted at a depth twice the width of the bulb. In Warm climates, plant suitable bulbs up to twice as deep as indicated on the packet. After planting, mulch the area in early morning when the soil is cooler and keep the planted area just damp until growth appears. For moon planters, Full Moon phase is the best time to plant bulbs.

Growing figs

This summer our area received a lot less rain than many other parts of Australia and, in March, dam levels were still low. However, a bonus of these drier than usual conditions was an excellent crop of figs. Ficus carica is a deciduous tree (usually about 6 metres high) that loves hot, dry summers as too much rain can cause the fig fruit to split, or develop fungal rot. Trees are frost tender in spring but mature trees are quite cold tolerant in winter.
The common figs (also called Adriatic figs) do not need pollination to produce fruit. Our tree is a ‘Brown Turkey’, which is one of the hardiest varieties with striped brown skin and deep pink flesh cropping from February to May. ‘Black Genoa’ has purple skin and red flesh not suitable for drying. It is a large tree cropping December to February. ‘White Cape’ has green skin and cream flesh that is excellent for jam. It is a compact tree that crops in January.
For gardeners in cooler areas of Australia, ‘White Adriatic’ (brown/green skin, pink flesh) that crops in February, and ‘White Genoa’ (green/yellow skin/ golden flesh) cropping December and February–March are recommended varieties.
Smyna figs need cross pollination with a caprifig to produce a crop and San Pedro figs only produce a small early crop without pollination.
Figs tend to be spreading trees, so choose a spot where they have room to stretch their limbs while providing you with lovely summer shade, but they respond well to a winter pruning to keep them to a manageable size. They are quite drought-tolerant when established and must have good drainage – a raised bed can assist this. They also love soil with a pH above 6.0 that contains a moderate amount of compost but don’t add a lot of other fertiliser as this can result in excess foliage growth and few fruit. If you do not have a lot of compost, an annual application 2 kg of poultry-based complete fertiliser and a drink of liquid seaweed fertiliser is usually enough. You will need to put netting over the tree as fruit begins to ripen – birds love figs.

It’s garlic sowing time

April is a good time to plant garlic in most areas. Garlic needs a soil that is rich in humus but doesn’t require a lot of nitrogen so avoid adding manures to the bed. Uncomposted manures can cause garlic bulbs to rot, although processed poultry fertiliser is quite suitable for garlic. Garlic needs a full range of plant nutrients and trace elements for healthy growth. A drink of seaweed extract tea over the whole planting area will supply a full range of trace elements. Garlic also needs a soil pH of that is close to neutral. Working a 5 cm layer of well-made aerobic compost into the topsoil will help to buffer the cloves from an unsuitable pH in surrounding soil.
We always sow garlic (and other bulbs) during Full Moon phase. That is from the 19th to the 24th of this month. Gardeners in areas with very mild winters can put the cloves (in a plastic bag) into the vege crisper of the fridge until then – because garlic likes a bit of a chill before starting to grow. As garlic needs dry conditions at harvest time, sowing in April usually allows the bulbs to mature before wet weather in late spring–summer.
Sow each clove (pointy end up) in a 5 cm deep hole, and water thoroughly. If sowing large quantities, place them 15 cm apart. Don’t forget to mulch the bed afterwards because garlic plants don’t like competing with weeds.

Luscious strawberries

strwbclsup1 A recent article published in BFA’s electronic newsletter, The Organic Advantage, quoted recent US research comparing organically-grown strawberries with those grown by conventional methods. Not surprisingly, the organic strawberries came out best for flavour, nutritional value, health-protecting antioxidant levels and colour, and stayed fresh for longer. The research was conducted across 26 farms and concluded that, not only was the organic fruit better, but the soil on the organic farms was higher in carbon and microbial activity, and had higher concentrations of trace elements. Soils on organic farms were also 30% higher in nitrogen than soils on conventional farms where synthetic nitrogen fertilisers were used.
There is nothing like the taste of organic strawberries. This probably has a lot to do with the fact that organic strawberries do not contain residues of the systemic pesticides and fungicides that are used on conventionally-grown strawberries.
I remember reading that strawberries were first discovered growing at the edges of pine forests in the northern hemisphere. This fact indicates three things, – that they will appreciate some shade from Australia’s intense summer sun; that they prefer a soil that is on the acidic side, and that they are dependent on mycorrhiza fungi in soil to assist them to absorb nutrients and moisture. Mycorrhiza-dependent plants absolutely thrive in organic cultivation because the humus in organic soils provides a habitat for beneficial mycorrhiza fungi.

When your strawberry plants start to flower, give them a drink of seaweed extract diluted to weak black tea strength. Kelp provides a good supply of potassium and a range of trace elements that are important in the formation of sweet fruit. The potassium also strengthens plant cells to improve disease resistance. Eco-cweed, Acadian, and Natrakelp are all products registered for use on organic gardens.
Water plants early in the day, too. Wet leaves at nightfall provide more suitable conditions for fungal diseases to establish.