Perennial Tomatoes

Everyone loves tomatoes, they are often grown as annuals and may people complain that they wish there were perennial tomatoes.  Well, there are perennial tomatoes.  I have seen seeds of perennial tomatoes for sale on ebay fetching serious money and I ask myself why.  Perhaps it is because people do not know about how to grow perennial tomatoes.  They are far more common than you think.

Indeterminate tomatoes can be grown as perennial tomatoes

Different types of tomato

There are many thousand different types of tomato, I am not exaggerating here, probably over twenty thousand recognised varieties world wide with a lot more being developed (by home growers such as myself as well as Government breeding programs) each year and a lot becoming extinct each year.  In the supermarkets we probably have access to half a dozen or so, by growing heirlooms we have easy access to several hundred varieties of all kinds of shapes/sizes/colours.  By growing heirlooms it is simple to save seed of the best varieties each year.  Of the many varieties of tomato that we have the easiest access to they can be roughly divided into two groups: determinate and indeterminate.

Roprecco Paste, a good determinate variety

Determinate tomatoes fruit pretty much all at once, then they tend to die, they are most easily grown as annuals.  They produce flowers at their terminal bud, after they flower that branch can not produce more leaves and stems.  These are great if you want all of your crop to harvest once, they are great for large scale farmers who only want to harvest once, as well as people who are into home preserving.  If you are planning on making paste or sauce then you probably want a determinate variety, there are several incredibly old and delicious heirloom varieties that are determinate.  I don't grow many of these, but I do grow a few, they serve their purpose well.  Some places claim determinate tomatoes are short and do not require staking, this is not always the case, please ignore anyone who makes such claims and stop buying seeds from them.

Speckled Roman, a good indeterminate variety

Indeterminate tomatoes can fruit over a long period, they keep growing as long as you protect the plant, they can be grown as perennial tomatoes if grown without frost.  They grow flowers from a side bud, not the terminal bud.  These are great if you want a few tomatoes each day or every few days, for many weeks/months on end.  Most varieties of tomato grown at home tend to be indeterminate, most heirlooms tend to be indeterminate (but there are some determinate ones too).  Some of these plants can grow massive while others can be rather compact.  Even though indeterminate tomatoes are perennial tomatoes they still tend to be grown as annuals.  Almost all indeterminate tomatoes are perennial tomatoes, no need to spend ridiculous amounts of money on "perennial tomato" seeds now.  Some places claim that indeterminate tomatoes are tall and require staking, this is not always the case, please ignore anyone who makes such claims and stop buying seeds from them.

Perennial Tomatoes

Many varieties of indeterminate tomato are a short lived perennial if grown in a warm climate, which is great if you happen to live in a warm climate.  Sometimes they can survive for several years but the productivity often drops off after the first year or two. 

I live in a frosty climate and have often wanted to grow the same tomato year after year, not just save seed, but keep the same plant going.  Even if you live in a frosty climate it is possible to over winter plants.  They probably won't produce a lot of fruit over winter (unless they are parthenocarpic), they will continue to flower but often the nights are too cool for fruit set, as soon as the weather is warm enough they will be ready and will ripen some early fruit for you.  This is a great way to get your plants to set fruit a few weeks to a few months earlier than from seed.

Overwintered Reisetomate set fruit 2 months earlier than the seed grown Reisetomate

Each year I overwinter some tomato plants.  Sometimes I do it because I am running low on seed, sometimes I do it because the plant was amazing and I want another season out of it, sometimes I do it because I am developing a new variety and would like to back cross its progeny with it to lock in a certain desirable trait.  Plants that are overwintered tend to crop a lot earlier and be more resilient than seedlings of the same variety.  Sometimes I overwinter a plant to help get an early crop and beat the extreme weather that we often get.

Yellow Pear tomatoes are simple to grow as perennials

How to overwinter an indeterminate tomato

This is one of those things that depends on a lot of different factors, mostly it depends on what you want to do and in which climate you are growing tomatoes.  You may wish to put up a shade cloth structure or something to protect a plant growing in the soil.  You may grow a plant in a pot that can be moved to somewhere safe.  You may live somewhere that the plants can be left as they are or just mulched carefully.  I take cuttings and overwinter these.

I take a cutting late in the season from the plant that I want to overwinter.  I use indeterminate varieties, while it is possible to use a determinate variety it is far more difficult as timing has to be just right and sometimes cuttings have to be taken throughout winter to prevent flowering.  Remember, if a determinate tomato flowers it will not grow any more or be able to produce new leaves or new sets of flowers.

The cutting will be genetically identical to the original plant, it is essentially the same plant.  I remove any flowers, remove the lower leaf or few leaves as they do not cope under water, then put the cutting into a glass of water.  The part I cut needs to be under water, the leaves need to be above the water, very simple.  You could plant the cutting directly into soil at this point instead of using water but I like to see the roots first so I use a glass of water.

Tomato cutting, ready to plant into soil

Normally in 3 days small roots appear, it may take a lot longer in cooler weather, it may be as fast as 8 hours in the right conditions.  The roots grow fast once they have started so I try to plant it into a pot of soil quickly.  Water roots are different from soil roots, so it is best to plant it after the roots are only short rather than wait a few extra days until they are long (like the picture below).  I then put this potted cutting somewhere safe over winter.

During this time it will grow and it should flower, mostly the flowers abort as the night temperatures are too low.  I grow them outside under the verandah against the mud brick where they get sun and warmth but no frost, if you live somewhere colder you could grow them inside near a window for light.  They need sunlight or they will become sick and attacked by insects.

This is the same cutting on the left, the second cutting was put in the water when the first picture was taken

After the frost has passed I often have a strong 3 foot tall flowering tomato plant ready to be planted out in the garden (or left in the pot and moved into the sun).  Quite often seed grown plants will only be 10cm tall at this time so the overwintered plant gets a significant head start.

This process of taking cuttings to overwinter can be continued indefinitely, each time you take a cutting you are restarting the clock and the plant will not die of old age.  If you have found a good F1 hybrid that you like and can not save seed from you do not need to buy new plants each year as you can simply take a cutting and overwinter the same plant.  You no longer need to waste money on 'perennial tomato' seeds, just look for a good indeterminate variety as they are perennial.

Far too easy, you now have perennial tomato plants even if you live in a frosty climate.  I sell some heirloom tomato seeds on my for sale page.  Many of these are indeterminate and can easily be over wintered, if you are interested please have a look.

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Edit to add:
I have grown tomatoes and overwintered them too many times to remember.  I am now wondering if in cold climates in small backyards if it is worth while growing them as perennials. 

Tomatoes grow so easily from seed and the space that they need over winter may be better used by something else that can not be grown from seed.  Overwintered tomatoes do fruit about 2 months earlier than seed grown, which is great, but space is so limiting now we live in town. 

I also have a few super early determinate varieties such as 'igloo' that will grow, fruit, and die before most other varieties start to ripen.  This means I can grow all from seed, have early tomatoes from 'igloo' and late tomatoes from other varieties and not have to protect anything over winter.