As soon as asparagus foliage has dried off, cut off stems to a few centimetres above soil level. The yellowish-brown colour of asparagus stems means that the plants have withdrawn nutrients and carbon compounds into their crowns to provide energy for new spring growth. Cutting back the stems while they are still green will gradually weaken the plants, and reduce the number of asparagus spears in coming seasons.
After cutting back the stems, remove any weeds from the bed, apply a generous drink of seaweed extract tea to the bed, and add a dusting of dolomite or agricultural lime. Asparagus are heavy feeders with a high nitrogen requirement. Give the bed a 3-5 cm layer of mature compost, or a 2 cm layer of worm castings, or a generous application of poultry-based organic complete fertiliser and a 3 cm layer of aged manure. Then cover the bed with a 5 cm layer of fluffed-up organic mulch. Fluffing the mulch allows rain and irrigation to trickle through to the soil. That done, apart from an occasional watering in during dry spells, you can leave nature to do its thing until spears start to poke their heads above ground in spring.
Soils for garlic need plenty of mature compost added, and they should have a a soil pH close to neutral for good growth and a rich supply of antioxidants.
The health benefits of garlic have been known for thousands of years, and this humble herb has been immortalised in carvings in Egyptian pyramids. We grow our own garlic because imported garlic is fumigated or irradiated, and some of it has been bleached.
Garlic is a member of the onion family, but it is more closely related to leeks in that family. In fact, Elephant or Russian Garlic (which can be identified by its large cloves) is not garlic but a leek with a garlic flavour, and it does not have the same health-protecting properties of true garlic.
Garlic for sale
We grow the ‘Italian White’ variety because it has a lovely flavour and suits our local climate. After filling our wholesale orders this year, we have kept a small quantity of certified organic garlic for sale direct to the public. You can buy 400 gram bags from us for a limited time.
• We have now sold out of garlic. New stock will be available around December 2010.
Garden peas that we sowed in early May have performed very well again this year and we have been able to freeze quite a lot. We have to net our peas to protect them from birds. We use arches of polypipe supported by garden stakes to hold the netting well clear of the plants, as King Parrots are clever at hooking the pods and pulling them through the netting. Pea flowers are self-pollinating, so netting won’t affect the size of your crop.
We grow our peas in soil with a pH of around 6.5, and we prepare the bed with compost and poultry–based complete fertiliser because peas won’t fix nitrogen unless the suitable rhizobium bacterium has been introduced to the soil. Once the seedlings had poked their heads above ground, we watered regularly.
However, cropping is almost over. We have left some well-filled pods about half way up the plants to set seed. They produce better seed than those saved at the end of harvest when the plants have exhausted most of their fertiliser supply. We have been saving seed from our peas since 2006, and get good germination without treating our seeds with any fungicide. Pea seeds are easy to save. Select only full sized pods that are full of seeds and allow them to mature on netted plants until the pods are brown and dry as in the photo. Ideally, they should be left of the plants until the seeds rattle in the pods but, sometimes, we have to harvest after pods brown, if rain is forecast. Don’t harvest pods for seed when they are wet, or the seed is likely to go mouldy.
The pods are spread on a fly screen frame, indoors, until completely dry and a fingernail will not make an indentation on the seed. The peas are then shelled and any blemished ones discarded. Seed is hung in an open paper bag for another week before storing in envelopes in an airtight container in a cool place. The benefit of saving your own seed is that it comes from plants that have grown well in your local microclimate.
One of my favourite vegetables is winter spinach, also known as English spinach. Spinach is rich in vitamins A, C, and E, folic acid, magnesium, iron, fibre, and contains some vitamin B6. It has a more delicate flavour than silver beet and, unlike silver beet, it can be frozen for use during warmer months. Winter spinach loves cold weather and a well-fertilised soil containing plenty of compost. It has a short growing period at our place because warm weather can extend into late autumn, winters are fairly short and mild, and temperatures rise quickly in spring, causing the plants to run to seed. Sow as soon as weather cools in autumn.
Fortunately, this vegetable grows very quickly, and harvesting can begin 8 weeks after sowing seed. From then on, leaves of all varieties of spinach must be harvested every day or two, or the plants will bolt to seed.
This year, Green Harvest sent to me seeds of their new open-pollinated variety – ‘Galilee’, and it has performed very well in our conditions. ‘Galilee’ was developed in the Middle East and is more tolerant of warm conditions than other varieties of winter spinach. It has produced a lot more foliage than the other variety we grow (‘Winter Giant’) and its mid green leaves have the same flavour as other spinach varieties. It is a great variety for gardeners who have struggled to grow winter spinach.
To freeze winter spinach: I wash the spinach thoroughly, roughly chop the leaves and stems, then put it in a steamer and blanch it with boiling water, before plunging the steamer into icy water. Then drain, and pack into ice cube trays or zip lock bags for freezing. Spinach in zip lock bags is pressed out to a flat sheet on a baking tray for freezing. This makes it easier to break off sections for adding to recipes.
Some gardeners are concerned because their peas are producing pods while their broad beans are not, although the plants are producing lots of flowers.
There is a difference in pollination methods between these two legumes. Garden peas are self-pollinating, and pollination occurs before the flowers open, so failure of pods to form is due either to cold or light frost damaging the blossoms, or the weather being too warm.
According to the Seed Savers’ Handbook, broad beans are partly self-pollinated and partly cross-pollinated, but we have noticed that our broad beans don’t form pods until bees are around. If it is too cold or too windy for bees to be out and about, the flowers die off without forming pods. Broad beans are also reluctant to set pods when the weather is too warm, but if it is still cool enough for peas to form pods, the problem is more likely to be a lack of insect activity. Keep the soil damp and give them a drink of seaweed extract tea. The potassium in that does help fruit/seed production. Oh, and make sure the bed is mulched – apply it early in the morning to keep the soil cooler for them.
There is a theory that removing the growing tips when they start to flower helps pod set. I have tried removing the growing tips on half of the plants and leaving the rest to grow naturally. It didn’t make any noticeable difference to pod setting.
If your broad bean plants haven’t been setting pods, get a medium-sized (about No 5) artist’s paint brush with soft bristles, and use it dry to ‘tickle’ the inside of the flowers to spread some pollen. If that doesn’t produce results, Have a chat with your seed supplier.
The ABC’s Gardening Australia program on June 20th told gardeners how to identify plants affected by bacterial wilt but, unfortunately, did not tell them how to eliminate the disease.
Bacterial wilt (Ralstonia solanacearum) is a serious soil disease that can, like Fusarium and Verticillium wilts, spread throughout the garden on boots, gardening tools, and infected plant material and seeds. It grows best in temperatures of between 30 and 35° C. and the bacterium requires both heat and moisture to multiply. Consequently, it is more commonly found in areas with wet summers.
It can affect the entire tomato family, the banana family (including Heliconia), onions, papaya, ginger, mung beans, cashews and peanuts. Like the fungal wilts, it affects the water-conducting tissue of plants and causes rapid wilting. Diagnosis can be determined from a section of stem pruned from near the base of a suspect plant. Immediately after pruning the stem, suspend it in a glass of clean water for several minutes. Milky threads will begin to leak from the stem and the water will quickly become white if Bacterial wilt is present.
Remove all plants, tubers and weeds from infected beds and destroy them, or dispose of them in a sealed plastic bag. Any remaining plant material can infect future crops of susceptible varieties – do not compost this material.
Raising beds to 20 cm or more can help deter this disease. After working on affected beds, wash boots and garden tools and allow them to dry in direct sunlight.
Bacterial wilt often occurs in conjunction with root knot nematodes. These pests can be eliminated by growing a green manure bio-fumigant.
Allowing a fallow of at least 18 months will also help, especially if soil in the bed is kept dry. This can be achieved by covering the bed with clear plastic, anchored around the edges. This process is called solarisation and it works best in warmer months, as bacterial wilt pathogens cannot survive in temperatures over 41° C.
After solarisation and bio-fumigants, grow a green manure of corn or maize and dig it into the topsoil. This will restore organic matter to soil and encourage the growth of beneficial mycorrhiza fungi. Bacterial wilt is more likely to occur in soil that is low in nutrients and organic matter, and has a high pH. Before growing crops in the treated beds, add plenty of complete organic fertiliser and as much compost as you can spare. Also check that soil pH is in the 6.5-7.5 range. Avoid growing susceptible crops in the treated beds for at least 3 years after diagnosis of the disease. Maintaining organic cultivation methods and practicing an adequate crop rotation will help prevent recurrence of this disease.
Autumn is a good time to check your citrus trees for magnesium deficiency. Citrus have a high magnesium requirement and magnesium is essential for the formation of chlorophyll (green colour) in leaves. Without enough magnesium plants will not be able to make sugars and starches, and growth will be poor.
Magnesium deficiency often shows up in citrus in autumn because magnesium is also required for developing fruit and many citrus species produce fruit over the cooler months.
Because magnesium is very mobile in plants, a shortage of this essential element results in magnesium being drawn from the older leaves to new growth. Deficiency shows as pale leaves, beginning with inter-vein yellowing of the outer edges of the oldest leaves, so that a green V remains with the point of the V at the leaf tip, and widest part of the V closest to the stem. In extreme cases, entire leaves may yellow.
Magnesium deficiency can occur in several ways. If soil is too dry roots can’t absorb magnesium, so regular watering of citrus is necessary. It is more common where soil is quite acidic and this can be remedied by watering in some dolomite, which will supply magnesium, plus calcium to raise the pH. If soil pH is in a suitable range for citrus, magnesium deficiency can also occur where heavy rain has leached it from soil, or where excess potassium has been added to soil – this includes use of wood ash, or overuse of seaweed fertilisers, which can cause a build up of potassium.
In these situations, a quick remedy to save this year’s crop is to dissolve some Epsom salts in a small amount of warm water, then dilute it in a full watering can of cold water, and water it into the soil under the outer part of the foliage canopy. You will need about 250 g of Epsom salts for a very young tree, and up to 2 kg for a fully-grown tree.
Magnesium is also important for sweetness of fruit. If your citrus fruits are not as sweet as you would like, it could be due to magnesium deficiency. However, a general yellowing or paleness of all leaves (chlorosis), while only the veins remain green, could be the result of iron deficiency. Iron deficiency begins in the youngest leaves. This can occur where soil is too alkaline for the tree to absorb iron. If the alkalinity occurred through an accidental overdose of lime or dolomite, the pH can be lowered by adding elemental sulphur to the soil around the tree. If soils are generally alkaline, including some well-rotted cow or horse manure that has NOT had lime added (under mulch, but not dug in) as part of your fertiliser will help reduce the pH by replacing some of the calcium ions in soil with hydrogen ions as it decomposes. To prevent crop losses, it is worthwhile checking soil pH around citrus trees each spring, and correcting it, if necessary.
See also: Feeding citrus
Autumn is a good time in most Australian gardening zones for maintenance work in the garden. My kitchen herb garden needed a serious renovation after three of our chooks escaped from their run during summer and made a total mess of everything. As summer was extremely hot and dry this year, I decided not to replant until after the weather cooled and we had some decent rain. Replacement plants were kept in the shade house until weather conditions were less stressful. In the meantime, I added some compost, worm castings, poultry based fertiliser, and seaweed tea to the soil; dug out weeds and errant roots of the mint family that had strayed far beyond their allocated area; and checked the soil pH. As it was barely on the acid side of neutral, I did not need to add any dolomite.
Although we grow some culinary herbs commercially, it is a nuisance to have to wander down to the herb beds when I want a few sprigs of something for a recipe. Consequently, my husband set up the framework for a kitchen herb garden close to the house. The finished garden measures 7 metres by 4 1/4 metres.
As the ground slopes slightly, the outer border of the garden was made from bricks retrieved from a demolished wall, and second-hand pavers provide pathways for easy access to all the herbs. The bird bath in the centre provides water for birds, bees and wasps that provide pest control and pollination. The garden has a permanent border of French lavender that serves several purposes. Lavender essential oils deter garden pests and, during the cooler months, the flowers are sold to a local florist. The hedge also protects the more delicate herbs from hot winds. There is a break in the hedge on the low side of the garden to allow cold air to drain away. A solid hedge traps cold air and allows frost to form. The herb garden also provides a suitable setting for my sundial.
I like to renovate my herb garden every three or four years as the perennial herbs such as rosemary, sage, thymes and mints don’t make as much strong, tender growth as the plants age. We find we get better production from younger plants that we grow from cuttings of the old stock. When I replant annual and perennial herbs, I always change their position in the garden as these plants also require a proper crop rotation to prevent soil diseases, and my herb garden is never completely full of herbs as I leave spaces for the rotation of annual and biennial herbs each season.
The garden looks quite bare at the moment (but it is easier to see the layout). I have very recently planted chives, rosemary, lemon thyme, marjoram, oregano, spearmint, eau-de-cologne mint, sweet basil, parsley, rose geranium, French tarragon and several more common thyme plants. The lemon grass clumps and the horseradish roots survived the chook attack, as did the soapwort. (Soapwort is not a culinary herb, but I didn’t know where else to put it). Coriander and dill will be sown later this month as they both do better here during the cooler months. After planting, the garden was mulched with finely chopped organic sugar cane residue as this will break down more quickly than other mulches, and add more organic matter to keep soil healthy.
Jenny has previously not had a lot of luck growing tomatoes and wants to know whether she should prune the side shoots that form on tomato stems.
When growing staked tomatoes, it is common practice to prune the small shoots that form in leaf axils because tomato plants do not have strong apical dominance. That means the leading shoot does not contain a lot of the hormone that prevents side shoots from growing. If left to their own devices, tomato plants produce multiple stems that flop onto the ground, producing additional roots from where stems touch soil. In removing the side shoots (by snapping them sideways when small, or cutting with a sharp knife when larger), growth is concentrated in the lead shoot. A second leader can be allowed to form from just below the first bunch of flowers and, once the plant reaches the top of the stake, you can pinch out the tip of the leaders.
This type of cultivation originated in cooler climates to allow more sun to get to the fruit by removing excess foliage, and make weeding easier. Where summers are hot, plants are better left unpruned once the main leaders are established because fruit can become sun scalded, especially where air pollution is low.
Where summers are very hot, tomato plants can do better under light shadecloth (which reduces transpiration) because it is actually warm air that allows tomatoes to ripen, rather than hot sun. As you know, tomatoes that have started to colour can be ripened indoors, although these will be lower in the anti-oxidant lycopene than vine ripened tomatoes.
Removing side shoots will also increase the size of fruit by limiting the amount of fruit that forms. However, other factors are more important in fruit quality. They are: providing a soil pH of around 6.5–7 because tomatoes will develop blossom end rot if they don’t have access to adequate calcium; providing sufficient well-balanced fertiliser such as mature compost, worm castings or poultry based fertiliser; regular deep watering rather than a daily sprinkle; and mulch to reduce fluctuations in soil moisture.
Just another hint: Plastic plant ties can cut into plant stems. When staking tomatoes, use a piece of knit fabric cut across the stretch, instead. Being more flexible, this type of tie won’t damage soft plant tissue.
As I mentioned in an earlier post, our broad beans were slow to produce pods because of an unusually cold winter. Broad beans are a combination of self-pollination and cross-pollination, and our broad beans do not start to set pods until bees become active in the garden.
Broad beans cease producing flowers when day temperatures are high (or when some pods have been allowed to reach maturity). Despite the shorter harvesting period this year, our small bed produced more broad beans than we could eat. During the harvesting period, I marked several of the healthiest plants and allowed the pods on these plants to fully mature for seed. In the photo below, the bean pods on the left are a perfect size to pick for use as a vegetable. The seeds in these pods are delicious and tender. Pods left on plants until they become spongy require both shelling and the removal of the outer seed coat.
The pods on the right of the photo are suitable to save as seed. Fully mature pods have lost their spongy feel and have become quite firm. It is recommended to allow pods to dry on the plants. However, as some of the pods were beginning to split (allowing the sun to damage the seeds), and rain was predicted, I brought the selected pods indoors to continue drying for a couple more days. Then I shelled the broad beans, and spread them on a flyscreen rack to continue drying. Seed is dry enough for packaging when firm pressure from a thumbnail will not leave a dent in the seed.
When saving seed from pea plants, follow the above advice for selecting suitable pods to save. Seed collected from pods near the base of pea plants is considered to be the best, but don’t let that deter you from saving seed if you have already picked those pods. It is best to leave pods on pea plants until seeds rattle within the pods. You will probably have to net the plants, or birds will eat the seed before it is ready to harvest. However, once pods have become thin-skinned and yellow, and rain is predicted, you can pull up the plants and hang them upside down indoors to prevent premature sprouting of seed. (If the pods a close to the base of large plants, I hang a portion of the plant for drying.)
When seeds rattle in their pods, shell them, and spread seeds on a rack for a few more days to ensure they are completely dry. Please note: unless your choice is extremely limited, only save seed from strong, disease-free plants that produce well-filled pods. If saving seed from pods that have some seeds missing, this characteristic can appear in plants grown from seed from those pods. Discard discoloured seeds and seeds much smaller than average. When seeds are dry enough for packaging, keep them in a paper container, inside a sealed container in a cool spot.