Farmer's Weekly (South Africa)
Fine-tune your cucurbit spacing
Back in the days when Boer pumpkins were planted almost exclusively, I got talking to a Limpopo farmer who had just delivered a load of pumpkins to a depot that distributed produce to mine kitchens.
When I mentioned the importance of spacing, he became thoughtful. Then he told me how, after transplanting fruit trees, he had decided to plant a row of pumpkins between each two rows of trees to maximise use of the prepared land.
In his experience, it was already too late for a good pumpkin yield due to the warmer weather, but anything he could harvest would be a bonus.
To his utter surprise, he harvested a record yield. Now he understood why, he said. For the first time, purely by chance, he had got the spacing right. As noted last week, spacing is all important. Each variety has its own optimal spacing, and a farmer should make the effort to carry out spacing trials for each variety planted.
He should also record the time of year, as this, too, plays an important role. For example, a specific runner variety that produces its first fruit 1,5m from the crown in summer will set its first fruit just 30cm from the crown when planted in a frost-free area in winter.
Other factors also play a role. On more than one occasion, I have come across a farmer who planted cucurbits in ideal growing conditions under a pivot, only to be disappointed when his yield was lower than that of his neighbour, who planted on dryland and gave the crop little attention.
Generally, the first farmer has attributed the difference to the lush growth preventing bees from locating the flowers. But, as I noted in the previous article, this is not so.
The reason for the low yield is that the fruit is aborted when the runners do not grow into sunlight. Although it seems counter-intuitive, we should space plants further apart under good conditions and closer together under less favourable conditions.
he doubled his planting density, but ended up with half the yield
wide vs close spacing: a case study
Some time ago, a client of mine planted one of my gem squash hybrids. I advised him to plant one row per bed, with an interrow spacing of 1,8m. He did this and had a yield of 80t/ha.
Then, against my advice, he planted another section at two rows per bed; that is, a row on each side of the bed. This effectively doubled the plant population.
To his consternation, the yield was half that of the section with the wider spacing.
When a person selling seed for a living advises you to plant fewer seeds per hectare, it’s time to pay attention!
conduct trials to find the optimal spacing
Farming is highly competitive and prone to many natural hazards. It is difficult enough to make a success of it when conditions are good. Therefore, to iterate, it’s important for farmers to conduct their own trials to maximise yield and reduce costs.
Apart from the benefit of higher profit, ‘fine-tuning’ in this way makes farming more rewarding and interesting.
• Bill Kerr is a vegetable specialist and a breeder of a range of vegetables. Email him at farmersweekly@ caxton.co.za. Subject line: Vegetable production.