How to Grow Micro Dwarf Tomatoes

tomato plant

How to Grow Micro Dwarf Tomatoes

Tomatoes are easy to grow either under cover or outside in a sunny position. There are many hundred varieties to choose from, producing fruit in a wide range of colours, shapes, sizes and flavours. 

Tomatoes are either Cordon type, also called indeterminate, or bush types, also called determinate. Cordon type tomatoes are usually trained as a single stem that effectively keeps on growing and can be over 2 meters high! Bush type tomatoes have a determinate size and are generally left to grow as they wish, within reason. 

There are many sizes of bush type tomatoes and in this guide we will focus on the tiniest of all. They are sometimes called Dwarf, Micro Dwarf or Windowsill tomatoes. It is important to know that some labelled Dwarf tomatoes can actually grow to over 1 meter high so it is important to read the description before purchasing the seeds. 

The Micro Dwarf Tomatoes referred to in this guide are generally between 15-45cm high and can therefore be kept in your S-Series mini greenhouse as long as you wish. They all produce delicious cherry tomatoes. 


Start sowing from mid winter to early summer for cropping in your S-Series. If you want to have the pots outside in summer, sow around 8-10 weeks before your expected last frost. Fill a pot, tray or multi-cell tray with peat-free compost and water it. Sow the seeds at least 2cm apart and cover lightly with compost or vermiculite – then water again carefully. Putting a plastic dome or cling film on top can help germination, but make sure it has air holes for ventilation. Keep the soil evenly moist until the seeds germinate because if they dry out they will most likely not germinate at all. Having said that, be careful not to overwater! Tomatoes will ideally need 18-26°C to germinate well and should appear within 7- 14 days. Once the seedlings appear, remove the plastic and place in a bright location with 12-16hrs of light. 18°C is an ideal growing temperature but they can tolerate down to 10°C. Any lower than that can really stunt the growth and damage the plants.

Plant care   

Transplant the seedlings to their individual 7-9cm pots when at least one set of true leaves have formed. Repot them into larger pots as necessary. It is worth noting that with Micro dwarf tomatoes the size of the plant can be controlled (to an extent) by the size of the pot. A smaller pot will give a smaller yield, so try to aim for a 15-20cm pot as the final one. 

You can keep the pot in your S-Series or put it outside in early summer after the last frost. To acclimatise the plants to outdoor conditions, lift them outside in a sheltered, lightly shaded spot during the day, and put them back in at night. Gradually increase the time outside, and do this for about two weeks before leaving them out all the time.

Try to keep the pots evenly watered and avoid splashing the leaves. Irregular watering can cause the fruit to split. Together with a lack of calcium uptake, can lead to blossom end rot, which causes the bottom end of the fruit to turn black. 

Feed every 10-14 days with a balanced liquid fertiliser, changing to a high-potash feed every 7-10 days once the first fruits start to set.  

Tomatoes are self-pollinating, meaning they have flowers that contain both the male and female parts and the pollen falls within the flower to pollinate itself. Wind and insects do help with this, so if you keep the flowering plant in your Sprout – give it a little shake every time you are there.


For the best flavour wait till the fruit is evenly coloured but don’t leave them so long that they go soft and split. 

Watch out! 

Every tomato growers nightmare is blight. Blight turns first the leaves, then the stems brown and eventually the fruit too. It quickly spreads and the plant will eventually die and all the fruit will become a brown mess. Blight can not be cured so prevention is essential! Growing under cover is the best solution – it tends to spread with wet weather when the conditions are warm and humid mid to late summer. Good ventilation around the plant and avoiding splashing water on the leaves and stems also helps. 

Pro Tip

Micro Dwarf Tomatoes are not trained like Cordon types, meaning suckers (small shoots that grow out from where the stem and the branch of a tomato plant meet) are not removed. However, remove one and pop into a glass of water and in a few weeks it will develop roots. Pot it up and see how long you can keep your plants going by doing this! 

Nerdy facts

Tomatoes are rich in lycopene, an antioxidant that is good for the heart and effective against certain cancers. They are also packed with Vitamins A and C, calcium and potassium. 

In a small Spanish town called Buñol  40,000 people throw 150,000 tomatoes at each other each year as part of a festival called La Tomatina.