Tired or Sick Soil
I had an interesting question by email today that I thought worth answering for everyone. Maria asks:
My husband grows tomatoes on the plot also in the greenhouse. Here’s the problem: this years tomatoes in the greenhouse are poor. We were thinking “tired soil” . Any suggestions?
When you grow the same crop year after year in the same place a number of things happen.
Firstly, the crop will take its nutrients from the ground and after a few years will have exhausted the precise balance of nutrients that it needs. This includes the micro-nutrients like iron and magnesium. A different crop will use different nutrient mixes so keeping the soil in an overall balance.
Secondly, pests an disease that are particular to the crop will build up in the soil. Pests and disease are always with us but growing the same thing year after year builds up the problems particular to the crop in much larger numbers.
My Greenhouse Answer
In my greenhouse I tend to swap sides each year. One year tomatoes, the next peppers and cucumbers. The soil will still get tired, despite my adding additional compost and fertiliser but it slows the process by half.
When getting the top soil from the garden, try to avoid soil that has recently grown potatoes, which are the same family as tomatoes.
What to do this year?
This “tired soil” syndrome or “sick soil” is well known and easily avoided. However, if you’ve got crops in their, you’re a bit stuck. My suggestion would be to alternate good tomato feed with a feed of Miracle Grow. The reason is that good tomato feed and more so Miracle Grow both contain a lot of trace nutrients which may help to balance the soil and stave off the problem for the season.
Shading the Greenhouse
There is another potential cause of the problem for Maria, the weather. Tomatoes like warm sunshine but it can get too hot for them. Ensuring there is plenty of ventilation helps but in really hot sunshine shading is a must.
Either drape green netting over the house or paint with shading compound like Coolglass – more on Greenhouse Shading Products.
Damping Down
Old gardeners used to damp down the house to increase the humidity in hot weather. This does deter red-mite but I’m told by the show growers it can cause rot and they prefer a dry atmosphere. Even when growing in borders, some of them water into bottles let into the soil by each plant to keep the surface dry. This also forces the roots down rather than spreading out.
Hope this helps a few people!
I suggest using ‘Chempak’ trace elements to perk up the greenhouse border soil as well as replacing the border soil it and adding some well rotted manure every couple of years.
I’m scared of suggesting manure since the aminopyralid problem came to light. Although it’s a good idea if you’re sure it’s ‘clean’