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.

Assisting root growth

We all know that an adequate supply of phosphorus is essential for healthy root growth but, during hot, dry months, we can further assist some of our vegetables to produce extra roots.
Pumpkins produce a huge amount of foliage – too much for the original root system to supply adequate water to the entire vine. Consequently, these plants and some other members of the squash family have evolved to produce roots at nodes (stem joints) along their runners. (See photo below.)
We can assist this auxiliary root formation by carefully lifting the runner and scratching the surface of the soil beneath where roots buds appear. Then cover this with a shovelful of compost and settle the runner back onto the compost. Encouraging extra roots to form will increase your crop.
These sections may be hidden by foliage but it will help to identify them if you place a soft drink bottle or large juice bottle (with the base removed) neck down beside this area. When watering, water not only around the base of the plant, but also into the bottles to supply water directly to the extra roots without wetting the foliage.

Tomatoes in their natural state, grow along the ground and will also 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 10-12 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.
You can also hill up soil around tomato plants (a little at a time), and sweet corn plants to encourage extra roots to grow on the lower parts of the main stem.

pmpknrootstmtroots