The more we grow spinach in the greenhouses the more disease we get. A classic case for better rotation. But, with limited tunnel space and our customers unending need for spinach, we have to keep growing it. Cladosporium on spinach
There are several ways that we have found to keep diseases to a minimum in the greenhouse. Many of these are just common sense but there are a few innovative tips out there as well.
- Keep humidity in the tunnel to a minimum. This may be the most important thing. Moisture in the soil or air helps with the spread of disease. If the inside of your plastic has water beading up on it, it is too wet. We keep our end vents open above 40 degrees as well as 2 small vents that stay open permanently.
- Avoid overhead watering or water early on a sunny day so plenty of time to dry out. Some growers have switched to drip, which they are finding works great.
- When disease does appear spray immediately to prevent spread. We usually hit it first with Oxidate, which helps kill spores. Then we will spray either Actinovate, which is a preventative group of good bacteria, or copper which protects the leaves and kills spores.
- Another way people are preventing disease is hot water treating seed. Many of the diseases come in on the seed, such as Fusarium or Cladosporium. Some extension services own hot water seed baths which they loan out to growers.
While researching diseases in our tunnels earlier this week, I came across this great resource about identifying spinach diseases.