Determinate: varieties are often referred to as bush tomatoes. This is because the terminal (top and end) buds end in a flower cluster that produces fruit. The plant will stop growing when the terminal flowers develop. The fruit then develops and ripens over a short period of time, depending upon the weather. Tomatoes like heat so in cooler summers this process will slow down. The determinate varieties usually mature early and will produce small plants with generally smaller fruit. The small size means they do not need to be pruned or staked and can be great for a balcony or patio, especially if space is limited.
these varieties are very popular with home gardeners. The indeterminate
varieties will they often produce high-quality, flavourful, desirable
fruit; they do mature later in the season than the determinate varieties
do. Indeterminate refers to the continual growth habit of the plant
which will continue to grow and flower until a killing frost. These are
tall plants and will require staking for best results. Pruning is also vital if you want to enhance quality. Both flowering and fruiting occur over a longer time period.
Semi-Indeterminate: the name says it all they have characteristics that are intermediate between determinate and indeterminate. Basically indeterminate in nature, they will need staking and pruning in order to improve quality, but this is not essential. The indeterminate varieties are also very popular with home gardeners as they can provide a fairly early and good-quality yield.