Tree tomatoes in the greenhouse
They look like tomatoes, but they don’t taste like tomatoes, and they are neither in direct family.
Photo: Sa Tang ©
By Lars Lund
Tree tomatoes are different and exotic, and they don’t taste like tomatoes. They are perfect for the greenhouse and can be used in an abundance of meals.
The common favourite plant in greenhouses is tomatoes. There is nothing like sun-ripened tomatoes, but do you know the tree tomato? It is one of the new plants I will try out in my greenhouse this year. Its Latin name is Cyphomandra Crassicaulis. Which I can pronounce perfectly of course. It is also called Tomarillo, not to be confused with the Tomatillo which I have grown but is not a favourite of mine.
The tree tomato is a shrub, which in its original growth area can get 3.3 feet tall or more. It carries oval red fruits and is used in both sour and salty dishes. The shape and size are like a chicken egg but pointy in both ends. The tree tomato stems from the mountains in Peru and has spread along the Andes Mountains. Today it can be found in large parts of Sri Lanka. Its original country tells us something about its needs. It needs a lot of heat, so it should preferably be placed in a greenhouse to ensure its growth. It can overwinter if it is placed frost-free, so it is not a plant you should throw away, as you can enjoy it for many years.
The fruits on a tree tomato plant can get 3 – 4 inches long and weigh up to 2.6 ounces. When ripe the peel is reddish-brown with longitudinal stripes. It is common that the colour inside and out varies. The peel is smooth and thin, and the pulp firm and golden.
Inside, the fruit is parted in two and the soft pips are in a jellyish mass. The peel tastes acrid and is rarely eaten. The juicy pulp has a delicious and fresh taste, which is both sweet and acidic.
You can use the pulp from a tree tomato for pickles or chutney. You can also make a nice hot sauce, by blending the tree tomatoes with chilli. Another option is to grill the pulp for 6-8 minutes and then add onion, coriander, lemon and salt. Half fruits of the tree tomato can be grilled and put on a pizza or you can mix fresh ones in a salad. A nice salad could be made from slices of tree tomatoes with crispy bacon, feta cheese and roasted almonds in an oil-vinegar dressing with mustard and brown sugar.
Inside they look delicious, and if you peel off the peel, they have a nice taste too. You can also eat the pulp with a teaspoon.
Photo: Albinus Frø ©
In salty dishes, you can use tree tomatoes instead of common tomatoes. The dishes will become a bit sweeter and get a more exotic twist. The tree tomato fits perfectly in the popular South American cuisine but avoids the peel. If you like the sweet better, you can cut the tomato in half, sprinkle some sugar on the pulp and eat it out of the peel with a teaspoon. It can also be used in jelly or jam, and it fits in cakes and pies as it has a fine balance between sweet and sour.
You can try a Tarte Tatin, which is a classic French apple pie with caramelised apples on top. You can just swap the apples with caramelised tree tomatoes. Serve with sour cream on top. Preserve the tree tomatoes with vanilla or bake them in puff pastry and eat with vanilla ice cream. You can also put pieces of the peeled tomato in a fruit salad with kiwi and mango.
The flowers remind of the potato’s flowers and they are self-pollinating.
Photo: Albinus Frø ©
Tree tomatoes are easy to seed propagate, but there can be a big difference in how long the seeds take to sprout. Often it takes between 3 - 6 weeks for the seeds to sprout. If you want to speed up the process you can put the seeds in the freezer for a day and then sow them afterwards.
Normally, they are sown in March because of the long growth time, but if you can store them frost-free during the winter you can sow them now. You can look for tree tomatoes in supermarkets to see if they are worth growing to you.
The colours change from green to orange or red/reddish-brown and often with longitudinal stripes.
Photo: Sa Tang ©
- You can expect the seeds to sprout within 3 – 5 weeks.
- You can speed up the sprouting by putting the seeds in the freezer for a day and then sow them right after.
- When sown the pot should be placed in a warm spot of 22 – 26 degrees, preferable with ground heat.
- The soil should be kept slightly humid.
- When the seeds have sprouted the plants grow relatively quick, so you have to change pots in the process.
- Grow the plant in the greenhouse during the summer. It thrives in a temperature of 18 – 20 degrees in the summer period.
- The tree tomato thrives in a nutrient-rich soil and you should regularly fertilize in the growth period.
- You can’t expect flowers and fruits on the plant until the second year at the earliest, often you have to wait yet another year.
- After the summer period, the plant needs a cool dormant period.
It should be kept frost-free but still cool (approximately 5 – 12 degrees) during the winter. During that period little irrigation is needed and you should not fertilize. It is the cold dormant period that boosts the flowering, so you should not keep the tree tomato at room temperature the entire winter, as there then won’t be any flower or fruit formation. During spring – around March – you can place the plant in a warm spot and slowly start irrigating and fertilizing again.
The flowers of a tree tomato are normally self-pollinating with no troubles, but if it looks like the plant is not setting fruits, you can help with a brush. Usually, the flowering on the perennial tree tomatoes starts in June, and then it takes a couple of months from the fruit formation to the fruits are ripen. Tree tomatoes ripen from green to orange to red, and they should be red before harvested.
Om Lars Lund
Danish horticulturist and journalist
Lars Lund has for many years engaged in the garden and greenhouse. Lars has published many books about greenhouses, and he has participated in many Danish horticultural TV shows. He is a walking garden encyclopaedia, and he has answers for most basic cultivation questions – also the more ambitious ones.