Spacing cucurbits – easier said than done

In years gone by, there were only open-pollinated pumpkins and gems. As seeds were so cheap, nearly all recommendations were for a generous number of seeds to be planted to make sure of a good stand. No thought was given to the influence on yield.
Issue date: 07 November 2008

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In years gone by, there were only open-pollinated pumpkins and gems. As seeds were so cheap, nearly all recommendations were for a generous number of seeds to be planted to make sure of a good stand. No thought was given to the influence on yield.

The fact is that spacing can have a huge effect. Too close, and there can be a drastic reduction in yield. To understand why, we have to go into the mechanisms of plants’ survival strategies in the wild before man used them for domestic purposes.
In nature, cucurbits would be scattered randomly among a lot of other wild plants, which we would call weeds.

It’s a very competitive environment where the plants can easily be swamped by vigorous weeds and left with very little sunlight.the cucurbits would therefore go into a vigorous growth phase after germination is established and dominate as much space as possible, to have more sunlight. When it comes to the critical reproductive stage of a cucurbit’s life cycle, the number of fruit it will bear is important.

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Remember that it must have enough nutrition, water and sunlight.If it overextends itself by setting a good crop of fruit, it may not have sufficient reserves to nourish the fruit to seed maturity. It may lose all the fruit and not pass its genes to the next generation.In these competitive situations, plants which are more conservative will set only one or two fruit and nourish them through to maturity.

Hence, the less productive plant could be more effective and the genes to set a conservative crop would then get passed on.he varieties which we now use still possess many of these survival mechanisms and by not understanding the ancient history of these plants, we get confused when we provide what we consider ideal conditions for growth and do not get the expected results. We need to consider that the plant can determine its growth when it’s under sunlight restrictions due to competition, but it can’t determine whether the competition is from the same variety or from weeds.

It just knows that it has to change its bearing habits on account of sunlight restriction due to competition.More on this subject next week. – Bill Kerr ((016) 366 0616 or e-mail [email protected]). |fw