Robin’s veggie growing tips of the month


Robin Gale-Baker, from Sustainable Macleod, has kindly agreed to provide this website with monthly, veggie growing tips.

Make your own heat bed (May 2019)

Heat beds provide an effective way of raising seedlings and plants during the colder months. They can be made above-ground or in-ground using fresh animal manure covered with a layer of soil or sand.

The purpose of an above-ground heat bed is to raise seedlings in punnets or plants in pots where they can’t tolerate cold roots in the winter. Such a bed is best placed inside a greenhouse or in a place protected from cold air. Simply create a box using wood or bricks, or even use a polystyrene box. Fill the base with fresh, preferably steaming, animal manure, and cover with 2-4cm of sand or soil. The decomposing manure will heat the layer of soil on top. Insert your seedling punnets or potted plants a couple of centimetres into the soil layer and you have a heat bed.

In-ground heat beds in the garden are used for plants that require higher temperatures than the soil provides for root development and growth. In our climate, this would include plants such as ginger, turmeric, galangal, cantaloupe and watermelons. For example, cantaloupe seeds require a soil temperature of 21°C to germinate and thus benefit enormously from this method as they can get a head start early in the season, allowing plenty of time then to set fruit and have it ripen. Dig a trench or hole 30cm deep, add 22cm of fresh manure, cover with 8cm of a mix of soil & compost, and plant into that.

Which fruits continue to ripen after being picked? (May 2018)

Pomegranates and figs are ripening beautifully at this time of year but must ripen on the tree (they do not continue to mature once picked). How do you know when they are ready? In the case of pomegranates, look for split skins. Once this happens to a few on the tree, all will be ready. It is worth investing in a pomegranate press (available online for less than $60) to extract the juice as the press will avoid inclusion of any of the bitter pith which ruins the taste. In the case of figs, look for wilting of the stem and give a gentle squeeze for softness. Note that pomegranates and figs that look like they are ready by colour often still have a way to go.

[Editor’s note: fruits that continues to ripen after being picked are called ‘climacteric’, whilst fruits that stop ripening after being picked are called ‘non-climacteric’. The archetypal climacteric fruit are tomatoes and bananas. Avocados, peaches and plums are also climacteric. The archetypal non-climacteric fruit are citrus. Grapes and all the curcubits (cucumbers, pumpkins, etc) are also non-climacteric. For each fruit, our North East Melbourne fruiting schedule lists whether it is climacteric or not. Climacteric fruit will typically only continue to ripen if kept at room temperature so you can defer this by putting them into the fridge until you want them to ripen.]

[Editor’s second note: have you ever seen the flower of a fig tree? The answer is ‘no’ because the flowers are actually inside the fig (and the fig is therefore not technically a fruit). Whilst common figs do not require pollination, they do not taste that good. Rather, the best tasting type – Smyrna – does require pollination. But it only has female flowers so needs to be pollinated by a wild/caprifig (whose fruit are inedible). As the flowers inside the fig are inaccessible to all normal pollen vectors, pollination is done by tiny wasps. The wasps hatch in the caprifig, then mate, then the females leave to find new figs to lay their eggs in. As they leave, they get covered in pollen, and pollinate the next fig that they enter. If it is a caprifig, then baby wasps are born but no edible fruit results. If, however, it is a Smyrna, then edible fruit results but no baby wasps are born (the Smyrna flowers are too long for the wasp to lay its eggs in). Luckily for you, the female fig produces an enzyme that digests the dead wasps completely and so the crunchy bits inside a fig are seeds, not wasp parts. For more info, watch this video.]

Plant annual herbs in autumn (April 2019)

It may sound odd to plant annual herbs in early April but I have come to the conclusion that it is a good idea. Herbs such as dill, florence fennel, summer savoury, coriander, chervil and German chamomile (the variety used for chamomile tea), all of which are used for their fragrant leaf, bolt during the hot summer months. Climate change has caused a shift in seasons so that once cool March and April are now warm – certainly warm enough to germinate seed – but not too warm to cause bolting to seed. You may not get seed head development but you will get foliage in autumn, winter and spring. Another advantage of autumn sowing of annual herbs is that this is also the time you can collect seed from last year’s plants, giving you fresh seed to sow.

Parsley, while technically a biennial, is usually grown as an annual and can be added to the list. It takes longer than the other herbs to germinate (up to 2 months compared to 10-14 days) but you can speed up the process by soaking the seed for 24 hours. If you are adventurous, you might also plant basil seedlings but, unlike other annuals, basil will succumb to cold weather and be killed off completely by frost. Having said that, my basil lasted into July last year.

Sow seed of all annual herbs directly into your garden so as to avoid setback through transplanting. Cover the seed in some way to prevent birds scratching it out and eating it up. And remember to water well from the time the seed is sown until the plant is well established.

When to pick pumpkins and how to ‘cure’ them (April 2018)

Pick pumpkins when the stem coming out of the top of the pumpkin has withered. Leave 10-12 cm of stem but don’t use it as a handle. You can also ‘knock’ on the pumpkin and if it sounds hollow then it is ready for picking. A pumpkin will not be ready to eat immediately after being harvested. Rather, it needs to be ‘cured’ (aka ‘hardened off’) and allowed to sweeten. To do this, rest the pumpkin on some mesh or wire so that air can circulate around it, with newspaper or straw underneath so that the skin doesn’t tear or blemish. Leave it in the sun for 2-3 weeks then turn it over and do the same for the bottom. Then the pumpkin will be ready to eat.

Vernalising your garlic (March 2019)

[Editor’s note: Robin and I debated garlic planting in some of the newsletters a couple of years ago. If you plant garlic too early (i.e. when it is too warm), the resulting bulbs may not divide into separate cloves. If you plant too late, the bulbs may remain small (because, driven by length of day, the garlic starts trying to form bulbs when it is too young). One potential way around this dilemma is to keep the garlic in the fridge for some time before planting. I experimented with different timings and different refrigerations and one of the conclusions was that refrigeration did, indeed, allow for later successful plantings. Read the results of the experiment.]

In the ‘old days’, before climate change, garlic would often be planted in March but these days the ground is too warm then (the perfect time to plant garlic is when soil temperature is 10°C at a depth of 8cm at 9am in the morning). Arguably, this is also becoming the case in April. So, commercial growers are increasingly giving their garlic a ‘false winter’ by refrigerating it for 40 days and then planting it out in May. This process is called vernalisation and helps late-planted garlic to develop large bulbs. If you want to copy these growers, you should be purchasing your garlic soon and refrigerating (not freezing) it in mid- to late-March. Buy from reputable sources (probably online or at farmers’ markets as nurseries won’t yet be stocking garlic heads) and do not use imported garlic as this may well have been sprayed with methyl bromide and a shoot inhibitor.

When preparing your garlic, select healthy heads, do not separate the cloves (as this could result in infection when removed from the basal plate), place in an airtight container in the fridge and remove 40 days later in May. Plant the large outer cloves at a depth of 2cm (i.e. the tip has 2 cm of soil above it) at 15cm intervals in rows 15cm apart, and apply a thick layer of loose mulch.

Garlic requires regular watering and, with drier winters, this needs to be done by hand, dripline or in wicking beds. In November or early December the plants will be ready to pull. Water up until 2 weeks before harvest. Ceasing watering then will allow the garlic to dry out, but also check the likely rainfall when planning when to harvest and adjust accordingly.

There are many varieties of garlic. They are broadly divided into soft-necks and hard-necks, with the soft-necks having a stronger flavour. Different varieties can have very different shelf lives.

For more information, read Helen Simpson’s guide to growing garlic.

Herb drying (March 2018)

A well-dried herb should be the same colour as it was in its fresh state. Those supermarket ones that are heat-dried, lose not only their colour but also most of their volatile oils. The best way to dry herbs is to cut the stems in the morning once any morning dew has dried but before watering, as this will be when the herb’s volatile oils will be strongest. Then tie them in bunches, remove any brown, dried leaves and hang them upside down in a warm but shady place to dry out. Once fully dry, strip the stems, fill the jars, screw the lid on, label and you’re done.

Some herbs don’t dry well and are better preserved in oil. These include basil (though recently someone told me that basil dried in a very slow oven retains its flavour), french tarragon, oregano, savoury and thyme. If preserving in oil, use a hot oil method as the microbes on herbs (or any other vegetable) can cause botulism (which can be fatal).

Watering errors (February 2019)

Recent high temperatures have highlighted that some people do not know the principles of protecting their gardens from extreme heat.

Imagine that you are a plant in a garden on a hot day. Would you prefer to be well hydrated before the heat hits or go into resuscitation mode when you are dehydrated, wilted or dying? Plants are just like us – they need to be fully hydrated before high heat and then re-hydrated afterwards. Many people make the error of watering only at the end of a hot day by which time their plants will have root damage, scorched leaves and sunburn, all of which is preventable. And just as we would wear a hat and clothing to protect our skin, plants need a protective covering of mulch around their roots and shade cloth or other covering (sheets, umbrellas etc) overhead to reduce water loss.

Under-watering is also a significant error and ultimately a significant waste of water too. Any time that a plant wilts, its roots are damaged (even if you water later and the plant seemingly recovers). Water close to the roots, directly onto the soil or mulch, or under the drip line of trees, taking into account how exposed to the sun the plant is, its size and whether it has extra water requirements. Identify which plant or plants in your garden wilt first and use this as a barometer of the dryness of your soil. Dig down and check the moisture content if you are not sure.

If you are watering a pot, it needs sufficient water to drip out the bottom which is where the roots will be. If it doesn’t drip, it is too dry. Even a small pot – say a 7cm tube which herbs are often grown in – needs at least a cup (250ml), and more if it is at all pot-bound. If you are not sure if you have watered a pot sufficiently, gently tap the plant out of the pot and check how far the water has penetrated. Often, it will be just the top centimetre or two and nowhere near the roots.

Finally, remember that it is the roots, not the leaves, which deliver water to the whole plant. The roots absorb water and channel it via the stem and branches to the leaves, flowers and fruits.

Seed saving (February 2018)

February and March are ideal times for seed collecting – both seed that has dried on the plant and wet seed which has to be extracted, washed and dried. Example wet seeds are tomatoes, pumpkins, zucchini, cucumber and capsicum. Consider collecting both early and late wet seed, particularly tomatoes, thereby selecting for plants that will produce both early and late in the season. Choose the best fruit, label clearly and plant at least one of each. You should be able to extend the tomato season until late May, if not early June. Note that pumpkin seed will often not grow true as it can be cross pollinated by bees from as far away as 8 kilometres (but you may get a variety of interesting pumpkins on the one vine!). You can, however, keep the seed true by either bagging the flowers or hand pollinating.

[Editor’s note: As Robin points out, you should keep back the best seed for planting, rather than follow the obvious course of eating the best and planting the dross. Incidentally, Richard Dawkins said (in The Ancestor’s Tale) that his father found this one of the hardest lessons to get across to farmers in Africa in the 1940s. If you want to know more about seed saving, an excellent book is The Seed Savers’ Handbook. Both readable and comprehensive, it would be a nice gift for anyone at $32. And here is a free booklet: A Guide to Seed Saving, Seed Stewardship & Seed Sovereignty.]

Tansy (Tanacetum vulgare) – the solution to ants! (January 2019)

A number of people have recently asked me how to deal with ants. Tansy is the answer. Tansy is a fern-like herb, growing to about 1 metre, with clusters of flattish yellow button flowers that make good dried flowers. It is a perennial but does best by being cut to ground level late autumn and allowed to shoot from the base. It will be the first plant in the garden to wilt in hot weather, indicating that your garden needs water.

Tansy has quite a history as an insect repellent and a biological pest control. It was used for embalming bodies, placed in coffins and made into wreathes which were placed on dead bodies. The tansy kept insects from attacking the corpses. As a pest control, it is used as a companion plant to roses, to cucumbers (repelling cucumber beetle), and in the USA with potato crops (to deter Colorado potato beetle).

Ants loathe tansy. Crush a tansy leaf and place it across an ant trail and the ants will immediately turn and run away. They will not cross the tansy leaf. Fresh tansy can be placed anywhere where you want to deter ants, or dried and placed in cupboards or drawers. It does have quite a pungent smell so that needs to be taken into account. At the Macleod community garden, where there was a considerable ant problem, tansy is grown behind the compost heaps and keeps them free of ant nests.

What is a compost activator? (December 2018)

A compost activator is a plant that activates and speeds up decomposition in the compost heap. It is the presence of potassium that makes a plant an activator. Potassium is found in sufficient quantity in the leaves of comfrey, yarrow, tansy, dandelion and stinging nettle and so you should put as much as you can of any of these in your compost layers. Comfrey also adds good quantities of trace elements which have been taken up by their very deep roots and deposited in the leaves, which then easily break down in the compost, releasing these trace minerals.

At this time of year, and during the hotter months to come, make sure that your compost is always moist throughout – decomposition will grind to a halt without moisture. Also at this time of year, there are plenty of fresh grass clippings available – add these clippings to speed up, and heat up, your heap, thereby killing any seeds that you have incorporated.

Growing passionfruit (November 2018)

Passionfruit, like blueberries, require quite acidic soil. They need a pH of around 5.5-6 so add granular sulphur, dig it in and then water in. Adding sulphur will also help release various trace elements like zinc and iron. Passionfruit are heavy feeders of iron so you may need to add some iron chelate. In our climate, Nelly Kelly is the best variety. The tropical varieties are sensitive to frost and do not survive. Planting passionfruit in front of a north facing wall gives them the best chance of success. They thrive in full sun and need wind protection and strong supports to grow on, as the vine quickly becomes very heavy. Prepare the soil by incorporating compost and well-rotted manure in an area 2 metres’ wide. Let the tendrils grow to the top of your trellis and then nip out the growing tip which will allow laterals to develop. Passionfruit require around 140 litres of water a weekly when they are fruiting. This is the equivalent of around 15 fullsize watering cans. Without this amount of water, flowers and fruit will drop.

Growing blueberries (October 2018)

Blueberries can be grown successfully in North East Melbourne but they do require exceptional soil preparation. The soil needs to be quite acidic with a pH of 4-5. However, our soils are naturally closer to 7 (neutral) so the pH needs to be reduced by at least 2 points. To do this, add granular sulphur, work it into the surface, and water it in. You may have to do this several times and it is best to begin the process 3 months before planting. Once your blueberries are established, you can assist the soil remaining acidic by digging in sphagnum peat carefully around the shallow roots once a year, and fertilising with an acidic fertiliser. However over time, the soil will return to its natural pH and your plants will suffer. Remedial action is then required to again reduce the pH. Plant in a sunny, well-drained position. One of the best varieties for our area is Brigitta.

[Editor’s note: in The Complete Book of Fruit Growing in Australia, Louis Glowinski recommends using well-rotted chicken manure as the fertiliser. His argument is that blueberries don’t like either nitrates or chlorides and that many commercial fertilisers contain such compounds.]

[Editor’s second note: one way of helping to keep the soil acidic is to use pine needles as the mulch. There are a number of pine trees along the Yarra, for example at Lenister Farm – simply take some big bags and scoop the needles off the ground.]

Crowns (September 2018)

Some fruit and vegetables are grown from crowns and these require careful planting. A crown is defined as a part of a plant where stem and roots meet. Examples are rhubarb, strawberries, asparagus and horseradish.

For rhubarb and strawberries, it is important that the eye or bud of the crown is planted at, or just above, soil level as this prevents crown rot. Each is best grown in a dedicated bed in sunny, moist, well-drained conditions and both do well with a generous mix of well-rotted manure and compost. Rhubarb should be divided after a number of years when it is clear that its production is waning. Use a sharp spade to cut through the crown making sure that each piece has an eye, and re-plant. Strawberries are grown from runners which develop from the original plant. Cut the stem between the original plant and the new plant, trim the runner of dead leaves and the runner stem, and re-plant. Both will produce in the season in which they are planted.

Unlike rhubarb and strawberries, asparagus needs to be planted deep in trenches and backfilled as the shoots emerge. The first spears should not be cut until the following season and then only 2-3 per plant. The season after that as many spears as you like can be harvested. Horseradish, on the other hand, needs little attention. It is grown from root cuttings – either small pieces of root that can be buried, or crowns. Plant the crowns so that the shoots are just above ground, and leave for a couple of years before harvesting, and remember that it is quite invasive!

Early heritage tomatoes (August 2018)

At this time of year – late July/early August – Bunnings sell a small range of heritage tomatoes from Diggers. You will find them in the indoor nursery section and this is for a very good reason: it is far too early to plant them out. However, if you have a greenhouse, or perhaps a sunny verandah, planting these early tomatoes in large pots of compost will give you advanced plants for putting in your garden in October, or even September if the weather is good and frosts unlikely. One advantage of doing this is that, as the plant grows, laterals will develop. Laterals are the shoots that grow between the main stem and a side branch. Normally they are pinched out to strengthen the plant. However, leave them until they are around 6cm long, pinch them out, plant them in potting mix and water well. Water each day and, within a week or two, you will have new plants with strong roots to plant out for no extra cost. A second advantage is that you could have tomatoes by Cup Day in early November! Traditionally, Cup Day has been the day that Melbournians are advised to plant out their tomatoes so you could be harvesting whilst your neighbours are only just planting!

Tending the raspberry patch (July 2018)

Now that winter is here, its time to tend the raspberry patch. First, you will need to know whether your raspberries are autumn varieties (e.g. Autumn Bliss, Autumn Heritage) or summer (e.g. Chilicotin, Chiliwack, Willamette) as they are treated in different ways. Both require wire supports. Autumn varieties prefer 2 sets of parallel wires each with 3 strands at intervals of 60cm and the taller summer varieties a single set of parallel wires with 4 strands at an interval of 50cm. Autumn varieties fruit on first year canes called primocanes and are usually pruned to ground level after leaf fall – pruning earlier or much later than leaf fall reduces the crop the following season. After pruning, add well composted manure to the bed. Then, in the spring when the canes reach 60cm in height, tip prune them and tie them to one of the horizontal wires – this will result in branching and more berries. Summer varieties fruit on second year canes called floricanes and are more complicated to prune. Canes that have fruited won’t fruit again, so look for dry, brown canes and prune these back to ground level. At the same time, look for new shoots or canes which will be green and tie them to your horizontal wire. Then tip prune them and fertilise with well composted manure. Both autumn and summer raspberries sucker. The suckers should be removed to keep the strength in the main cane. Cut the suckers rather than pull them.

Quick composting of leaves (June 2018)

Nature is currently providing us with an abundance of raw nutrients for next season’s garden in the form of leaves and grass clippings, both excellent ingredients for composting. Deep-rooted trees pull trace minerals from deep in the soil and deposit them in their leaves. Leaves contain twice as many minerals as the same weight of manure. The main problem with using leaves is that they mat and this creates a barrier to air circulation and water absorption and consequently slows the composting process or, in some cases, stops it altogether. There is an easy solution to this: mow or shred your leaves. This reduces their size and creates many leaf edges that are then easily accessible to microbes that break down the leaf structure. A rotary mower, shredder or even a whipper snipper will do the job.

To begin your compost heap, select a site directly on soil and start building layer by layer. Begin with a layer of shredded leaves about 100-150mm thick, then add 50-100mm of fresh grass clippings. By the next day, the clippings will have created considerable heat. Add some animal manure. Fermented vegetable scraps can be added next (such as the contents of a Bokashi bin – Bokashi mix is full of microbes and a scattering of this alone will speed up composting). Repeat these layers until the heap is 1-1.5 metres high and has a similar width. Make sure you water each layer as dry material will not compost. Add a ‘heavy’ layer to the surface to prevent any leaves blowing away – this could be soil, hessian bags or chicken wire. The final step is to turn your heap regularly and, as the leaves are light, this won’t be heavy work. Leave the heap for a fortnight, then turn every 3 days for rapid composting until you have a rich, black humus which you can either dig into your soil or add as a layer of mulch.