When to switch to shade cloth

[Misterpatrick]

Hello all,

I have a couple raised beds where I have just started lettuce and greens under hoop plastic. I'll be moving out the cauliflower, broccoli etc later this spring. My question is for cauliflower and other cool-loving things at what point in the season do you switch to shade cloth to prevent bolting? I'm in zone 4 in Minnesota.

[applestar]

Ooh this is a good question. In the past, I've planted cauliflower and broccoli where they would get shaded by a tree from midday sun, and had them under a white mesh insect cover to exclude the cabbage butterflies and moths -- not real shade cloth, but does filter the sun a little while still maintaining ventilation (floating cover stifles and actually gets hot inside). That worked out well. But it's a timing issue, too, and how your summer unfolds.

It might help to put a remote thermometer sensor out there (or be out there every day with a thermometer) and monitor the actual temperatures in the sun. I'm thinking when it gets to be 80°F in the shade (official temperature) might be about the right time, but I would like to hear from people who have done this before.

[imafan26]

Lettuce does do o.k. until it hits around 80, so that would be a good time to start shading. We also switch to the more heat resistant varieties like the frizee, butterheads, and red lettuce.
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