To obviate the necessity of staking, you can grow the crop in a very dry area, or at a dry time of the year – which is possible in subtropical areas in winter. The first problem is moisture on the ground, as the foliage and fruit can get diseased if they come into contact with wet soil. Even in dry conditions, there will be some losses and downgrading of fruit, but this may work out to be less than the cost of staking. Most processor tomatoes are grown in this manner, and compact, determinate varieties are bred specifically for this purpose.
It goes without saying that, with this style of planting, you must avoid overhead irrigation. Instead, drip irrigation is used. This makes for economic water usage and better control of application. With a very small surface area wet there’s less chance of ‘disease promotion’. Drip irrigation also allows you to apply fertiliser dressings accurately – another advantage. Alternatively, you can use furrow irrigation. Here, you plant the tomatoes alongside the furrow and move the foliage away from the furrow as the foliage grows, ensuring minimal contact between the plant and the wet soil.
This method wastes water, requires greater skill to get the correct fall for the conditions and is more labour intensive. For all this, though, it’s a cheaper way to get started. You can switch to drip irrigation when your finances allow for it.Another potential problem when growing without stakes is that spraying for pests and, especially, diseases can be more difficult. With a staked plant, your spray apparatus should enable you to wet both surfaces of every leaf.
This becomes impossible with plants lying on the soil, therefore the potential for disease increases. This can be partially overcome by using systemic products, but these are expensive and there’s a greater risk of the plants acquiring resistance to the products through overuse. The two main markets for tomatoes grown under this system are for processing and for on-farm sales for the hawker market.
Many of the varieties bred for processing are also bred overseas, where mechanical harvesting is practised. Such varieties must have a concentrated growth habit, uniform maturity and the ability to stay in a usable state for an extended period to allow all the tomatoes to be ripe at one time for harvesting as there’s no possibility of a second pick with mechanical harvesting.
Apart from this, processor tomatoes must have a deep red colour and high solids for maximum return of processed product per hectare. These requirements can also suit the hawker market in many cases, but this will vary from district to district. The fact that most processor varieties have elongated fruit may suit some and not others, as many hawkers want round tomatoes.
I believe this is largely because farmers who grow for supermarkets make the reject tomatoes (which are round) available to hawkers at a good price. Still, with so many varieties to choose from these days, there are many compact, round, long shelf life tomatoes available to suit any market condition.
Another consideration when choosing a variety is whether you want a concentrated bearer or one which provides a more extended harvest. The total yield may be similar, but the advantage of a concentrated bearer – which would suit a processor – is that once you’ve harvested, there’s little left to pick, meaning you’ll have to plant smaller areas and plant more often.
On the other hand, the advantage of having a larger area with a variety with an extended harvest may be outweighed by the possibility that, during the first and second pick, the plants still growing may be mechanically damaged and get sunburn. This means more supervision. Consider all these aspects when starting off and fine-tune as you go along.
Contact Bill Kerr at [email protected]. Please state ‘Vegetable production’ in the subject line of your email.