Night-frost in May
Don’t put your bubble-wrap too far away.
Night-frost at the beginning of May, oh no. That is not exactly something your new tomato plants in the greenhouse are fond of. Rather, they can die from it.
Luckily the bubble-wrap has not been hidden away, so put it around the tomato plants to keep them warm. A small petroleum heater or some candles can also do the trick.
It is the ideal time in May to transplant tomatoes that have been sitting in the window inside. They now need better light and natural humidity.
My Thai neighbour still thinks she is living in Thailand and challenges me by during everything you don’t do. She even succeeds in transplanting cucumbers in late April.
Normally, you plant cucumbers around the 1st of June, but she does it in late April. The only explanation I have for it succeeding is that she transplants them in her greenhouse by a south-facing wall. The wall is warmed up when the sun is shining, which keeps the greenhouse warm at night. Every year she comes to my house with a big smile and her home-grown cucumbers. They are almost ready before I have even transplanted my own.
They came early and now we might get night frosts.
The risk of planting cucumbers too early is that the harvest might be inferior. A tomato plant brings most tomatoes if the temperature is between 14-18 degrees when blooming. So, if May is cold and you transplant early, you might need to bring extra heat to the plants.
If you have bought tomato plants with flower branches the risk is, of course, lower but remember not to expose the plants to too much cold if they come from a warm nursery.
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.