Photosynthesis
In a previous article I talked about air movement for transpiration, reducing condensation and helping to prevent diseases.

In this article I want to mention the importance of reflected light and air movement for photosynthesis.

We touched on photosynthesis in a previous newsletter but here are some practical tips that we can apply.

Quick re-cap:
Photosynthesis is the way plants make their own food – they use:

  • Light – directly or indirectly from the sun
  • Water – usually from the soil
  • Carbon dioxide absorbed through leaves – from the air around them.

If one of these is in short supply, growth will slow down.

It’s easy to provide the water, but providing enough light and carbon dioxide is more challenging.

Light
Two season ago in the UK, was the worse for growing tomatoes I’ve ever experienced. Usually too much rain is the problem – last season the biggest problem was providing enough light.

Even my cherry varieties struggled to produce ripe tomatoes let alone the medium and beefsteak ones!

Reason … not enough light.

Tomatoes don’t need full sun all day for photosynthesis and to produce a good crop. In fact, some varieties can make do and create enough energy (sugars) from photosynthesis with very little direct sunlight as long as there is enough reflected light available.

Reflected Light
White reflective surfaces increase yield and can be used from the seedling stage to mature fruiting plants. Even a sheet of white paper behind a tray of seedlings helps.

Aeration
Greenhouse aeration (air flow) helps to make carbon dioxide available.

A sealed greenhouse full of tomato plants, with no new air flowing in, will use-up the available carbon dioxide and growth will be reduced.

Two big tips this season
Use reflective material as much as possible throughout plant growth. Use white plastic sheeting, sheets of paper behind seedlings and even paint fences or walls white if you are growing outside.

Keep the air circulating in the greenhouse – it’s better for the temperature to be reduced slightly than to have a greenhouse full of condensation and air without enough carbon dioxide.

Tip: Professional growers provide extra carbon dioxide for their plants. If you are a home brewer, fermentation gives off carbon dioxide – growing tomatoes isn’t the only use for the greenhouse!