Indeterminate & Determinate Tomatoes

tomatoIf you have taken a look at the market garden lately, you might have noticed that Mark and I have constructed a tall stake-and-wire trellising system for many of our tomatoes.  This system will allow us to guide our indeterminate tomatoes up an 8ft piece of twine as they grow.  We will prune the ‘suckers’ from these plants to promote upward growth. Our determinate type tomatoes, will be supported by a shorter basket-weaving trellising system that will be less noticeable from the road.

We are constructing two different trellising systems because some tomato varieties(indeterminate) grow very tall up a central stem and other varieties ‘self-top’ at more manageable heights(determinate).  Here’s how I remember what indeterminate and determinate means–the height of determinate tomatoes is determined (usually under 6 ft) while the height of indeterminate tomatoes is not (they will grow until the central stem is pruned).

Home gardeners can use tomato cages to successfully support both indeterminate and determinate tomato varieties.  Although pruning is not necessary, indeterminate tomatoes may need to be pruned so that these free-wheeling tomatoes don’t take over your garden.  In contrast, determinate tomatoes should not be pruned.  Removing the suckers from determinate varieties will reduce your crop yield.  I prune only the bottom-most leaves and suckers from my determinate tomatoes because I don’t want foliage touching the ground.

Indeterminate and determinate tomato varieties also have different patterns of fruit production.  Determinate tomatoes produce a crop all at once.  This is great for gardeners who want to preserve their crop by canning–you can pick all at once and put everything up.  Roma, a popular canning tomato, is a determinate variety.  Indeterminate tomatoes keep producing fruit throughout the growing season.  This is great for growers who want slicing tomatoes.  It’s nice to have a few tomatoes ripening at any given time.   (Note:  All tomatoes tend to stop setting fruit when temperatures climb consistently into the mid 90’s.  This happens sooner than we’d like in Central Texas.)


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