These are often called husk tomatoes.

I have a few varieties including michoacan, verde (usual green), a full purple variety and a large green tennis ball sized variety from Tuscon Arizona.

They grow easily in a warm environment but will still grow and produce anywhere you can grow a tomato – and seem even slightly more cold tolerant but will be smaller and fruit a bit less. They follow the same basic flowering and  fruiting pattern as tomatoes. And they need the same level of feeding, water and heat to produce well.

The plants tend to sprawl widely and I have found tying them up on stakes will help with collecting the fruit.

I leave them till the fruit has filled the husk or is splitting the husk open and it all naturally gives way in your hand when you pull it off the stem. It is usually still fairly hard to the touch when it comes off the stem. Sometimes the husk will grow quite large and then take some time for the fruit to fill it out. One variety I have grows enormous husks but has average sized fruit that never breaks the husk even when fully grown – but another variety always fills and breaks the husk. Some varities also have attractive purple or red veins on the husks.

Fallen fruit is also perfectly ok and will continue to ripen for some time once picked.

I recommend grilling them to get the best flavour, but they all taste great chopped and simmered and made into mole or salsa. They hold a lot of moisture inside them.

Also see my efforts with a simple Tomatillo paste

      

These tomatillo plants are growing along side a selection of other cuisine related plants such as Tagetes minuta – Black mint which helps keep the bugs under control.