Corn – improving pollination

All types of corn are pollinated by breezes that blow pollen from the male flowers onto the silk threads that emerge from the top of each ear of corn. This is why it is better for home gardeners to grow corn in a block rather than a long row. Each strand of silk is connected to a separate immature seed and is covered in tiny sticky hairs that collect the pollen. If some silk strands don’t receive pollen, kernels may not form along one side of a cob, or near the top of the cob. (Female part of corn plant in photo at left.)

Male flowers form at the top of the corn plant as an upright spike and lower branches that open out like umbrella spokes. Pollen forms in small yellow ovals (anthers) that release their pollen mid morning after dew has dried from the flowers (between about 9 and 11 am). The centre spike is the first part to release its pollen. Pollen release may only last from 3 to 5 days and the released pollen is only viable for up to 24 hours. (Male flower in photo at left.)
It can help when growing small quantities of sweet corn or popcorn to pollinate it by hand, to ensure that the cobs your plants produce are full of juicy kernels. In nature, silks are rarely pollinated by the same plant.

To ensure good pollination, you need a sheet of A4 paper and a clean, dry, soft paintbrush. Fold the paper in half lengthways and open it out, then fold it in half the opposite way and open it out. This helps the paper to form a shallow well. Or, you can use a small clean shallow tray – something easy to manoeuvre between the plants. Hold the paper under a male flower and gently tap the spike and lower branches of the male flower with the handle of the paint brush. When tassels are ready to be pollinated, plenty of bright yellow pollen will fall onto the paper. Collect some of the pollen on the hairs of the paintbrush and dab it onto all sides and the centre of silk strands of other corn plants. Repeat this process over several days. Once a tassel has been pollinated, the ends of the silk strands will start to turn brown. As the cobs mature, you may have to net your corn crop as birds know when corn is perfect for eating.
Corn anthers won’t release pollen when conditions are too wet or very dry, the plants will wait until conditions are favourable. In areas of Australia that experience long periods of rain, it is best to plan your corn crop to avoid the wet season.

Snake beans

Snake bean vine Snake beans are a good value crop for the vege patch where summers are hot, and French beans may struggle or be attacked by birds. They are prolific croppers over a long period and 4 plants are probably sufficient to supply a family of 4. Ours were still cropping at the beginning of June this year. A popular ingredient in Asian dishes, they can be substituted for French beans in many recipes, and blanched, young beans can be added to salads.

Snake bean pods Snake beans can grow up to half a metre or longer but tend to become a little tough if allowed to grow to this length (i.e. the beans at the bottom of the photo). They are best eaten when 30 cm or so in length while seeds are small, and they are young and tender. Pods grow fast and should be picked every day, or every second day at least, to ensure that they are harvested at their best, and to keep the vines forming new pods.
Snake beans take up very little space in the garden as they are grown on a trellis in soil that has plenty of compost and some organic complete fertiliser added, which should keep the soil pH at an ideal level (6.5–7). In late spring, when soil temperature is at least 15 degrees Celsius, sow seeds in damp soil 1 cm deep and 30 cm apart. Water to settle soil after sowing. Do not water the soil again until seed leaves appear, then water regularly to ensure healthy growth. In tropical areas where summer rainfall is heavy, sow seeds in hills to improve drainage. Seeds germinate quickly, and vines can produce pods in 60 days in very hot weather.
Snake bean ripening Greenpatch Organic Seeds has two varieties of snake bean; one with black seeds that produces pods up to 45 cm and one with brown seeds than produces thin pods to 60 cm.
Allow a couple of pods to mature until they have yellowed and lost their ‘puffiness’ (see photo). Then continue the drying process indoors. De-pod seeds when pods are crisp.

Time to plant spring bulbs

Just a reminder that April is a good time for planting spring-flowering bulbs in most areas. Gardeners in warmer climates can put bulbs into the vegetable crisper of the fridge for a month’s chilling before planting in May.
Add plenty of compost and some complete organic complete fertiliser to the planting area. Nutrients will be absorbed by the plants during the growing season and withdrawn into the bulbs as the foliage dies back to ensure good flowering the following season, so remember not to remove foliage before it becomes brown. 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, then water regularly. For moon planters, Full Moon phase is the best time to plant bulbs. This year (2014) the Full Moon occurs on 15th of April and May.

Garlic planting time – again

garlic1 March and April are good months for planting garlic in temperate to warmer parts of Australia. This year we are going back to growing the ‘Italian White‘ variety as our winters are becoming too mild for the hard-necked varieties. ‘Italian White‘ is a soft-necked garlic more suited to warmer areas. Cloves are slightly smaller than the purple hard-necked garlic but it has a lovely flavour and keeps longer than the hard-neck varieties.

We will sow ours in the middle of April (during Full Moon phase), after separating the knobs into individual cloves. The larger cloves from each knob will be planted, flat end down, just below the surface into soil rich in compost with a pH close to neutral. We usually plant our cloves 15 cm apart in rows 30 cm apart so that the canopy formed by the leaves helps to keep the mulched soil cooler. Garlic needs regular, deep watering (not a daily sprinkle) and hates competing with weeds. Green Harvest has a range of garlic for planting, and their garlic page will help you to decide which variety is best suited to your local climate and needs.

If you want to grow a small quantity of garlic from knobs purchased from your greengrocer, make sure it is Australian garlic. Imported garlic is treated with methyl bromide, a nasty gas that has been banned in Europe and may prevent cloves from growing.
Garlic takes 6 to 8 months to develop a bulb depending on the variety and climate.

Scallions or Spring onions

True scallions (Allium fistulosum) that originated in the Far East do not form a bulb. Also known in Australia as spring onions or green onions, these onions are a versatile herb that are used as raw or cooked vegetables In some areas they are sold as shallots, however, true shallots (Allium aggregatum) form a light brown bulb. Scallions are harvested as required as they cannot be stored for long periods. Their pencil-thick stems and hollow green leaves provide a mild flavour used raw in salads, or cooked in many Asian dishes. Chinese herbalists value them for various medicinal properties.
Scallions are easy to grow in all climate zones in Australia, and can be ready to harvest in 8 – 10 weeks. Young seedlings respond well in a compost-rich soil and an application of weak, fermented manure tea watered in several days after transplanting.
Seed of green onions does not keep for long and seed collected for sowing next season will produce a vigorous crop as this seed will have come from plants that have adapted to your local soil and climate conditions. Leave several of your green onion plants to produce seed from their globular flower heads (umbrels).
To save seeds from your spring onions, see Spring onions – saving seed

Test compost pH before use

pHkit.jpg

It is wise to test the pH of compost (including homemade compost) before adding it to your topsoil because the pH of topsoil determines which nutrients are available to plants. Well-made aerobic compost has a pH of around 6.0 to 6.5. Unfortunately, I didn’t follow my own advice recently when, temporarily short of homemade compost, we purchased from our local Bunnings store some bags of Richgro ‘All Purpose Organic Compost’ registered as an allowed input by BFA.

I noticed that the transplanted seedlings where I had applied the compost were not making any growth although the rest of the vege patch was doing well. And, in the area where I had mixed extra compost through each planting hole, the seedlings had turned yellow – a clear sign that the soil pH was too high for the plants to absorb phosphorus for root growth, or iron. Iron (along with nitrogen and magnesium) is essential for chlorophyll (green colouring) formation in leaves that allows plants to produce carbohydrates for growth. Iron deficiency (iron chlorosis) starts in the tips of plants and the leaves of the whole plant turn yellow between the veins or, in extreme cases, white. In contrast, nitrogen chlorosis starts in the older leaves because, when nitrogen is in short supply, plants transfer the available nitrogen to the growing tips, and magnesium deficiency starts in the margins of older leaves.
I tested the topsoil of the affected areas and, finding it above 7.5, I then tested the Richgro compost and the reading was between 8.0 and 8.5. As the pH scale is expressed as negative logarithms, a reading of 8.0 means that the soil is ten times more alkaline than a neutral reading of 7.0. This week I received a question from a blog reader who is having difficulty reducing his soil pH. He had also used the same brand of compost, bought from Bunnings in WA.
Richgro’s response that their “internal records” of the batches in question show a pH of 7.1 and 7.2 and that the test kit I used “do not work well with high organic fraction soils or composts” blah, blah, is not consistent with the physical symptoms of the seedlings. I suspect the problem may have been caused by the type of timber used to produce biochar added to the product. Wood ash contains a very reactive form of calcium and, as the ‘Gardening with Biochar’ website states, Raising soil pH is biochar’s most important contribution to influencing soil quality.
* I must add that Bunnings were quite happy to accept return of the unopened bags of compost after I explained the problem.

To test pH
Add equal quantities of topsoil from the bed you are preparing and the compost you intend to use to a clean bucket. Mix thoroughly, then mix again. Test a sample of the mixture according to the instructions on your soil test kit. Ideally, for healthy growth of most plants, the pH reading should be between 6 and 7.2.
If soil pH is higher than this, please see: ‘Changing soil pH’
Also see: ‘What’s soil pH?’

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

Kid’s vege patch

Primary school children have opportunities to learn about sustainable gardening at school, including the Organic School Gardens program provided free to all Australian school students by Biological Farmers of Australia, but younger children can also have a lot of fun learning to grow their own fruits and vegetables.
Although they have a shorter attention span, very young children learn quickly when copying adults especially when they have a small patch of soil or some large pots for their own organic garden. International research has shown that children are more likely to enjoy eating vegetables that they have grown themselves, or helped to grow.

Vegetables that mature quickly or are miniatures are appealing to small children. Small lettuces such as heat-tolerant ‘Little Gem’ or ‘Mesclun Mixed’ and cherry tomatoes: “Tiny Tim’, ‘Tommy Toe’ or ‘Yellow Cherry Cocktail’ are fast-maturing. ‘Butter Bush’, ‘Provider’ and ‘Strike’ produce small pods of beans with good flavour. ‘Little Finger’ carrots mature quickly and ‘Bolthardy’, “Bull’s Blood’ or ‘Golden’ beetroot harvested as baby beets are rich in health-protecting antioxidants. ‘Golden Nugget’ is a small bush-type pumpkin and children enjoy digging for ‘chat’ potatoes in summer.

In cooler weather, ‘Di Cicco’ broccoli, ‘Snowball’ cauliflower, ‘Sugarsnap’ and ‘Oregan Snow’ peas, milder flavoured ‘Bloomsdale’ English spinach and baby leeks harvested when 2 cm thick can all be appealing to children.
Strawberries, melons and corn all take longer to mature but are popular with children. ‘Minnesota Midget’ rockmelon and ‘Sugarbaby’ watermelon are fast-maturing; ‘Golden Bantam’ sweet corn and ‘Golf Ball’ or ‘Ontos’ popcorn usually produce multiple cobs per plant. Corn is a whole grain, and organic popcorn is a popular and healthy snack food for kids. (See Growing popcorn)
Seed varieties mentioned above can by obtained from Eden Seeds or Greenpatch Organic Seeds.

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.