I have a patch of beets that I planted from seed, and I need to relocate some of them, because thay are too crowded. Can I transplant them now, or should I wait until the heat wave is over?
Your question is a good one: the most popular means of dealing with an over-abundance of vegetable seedlings is by thinning out the weaklings (preferably cutting at soil level with scissors) when crowding threatens to become an issue. Especially in the case of most root vegetables, the option of transplanting is generally not employed, as the deep-growing tap roots (that transport the xylem and phloem) establish early, and are easily damaged in the process.
However. The rustic, robust table beet plant (as different from sugar beets) with its rotund tap root, has proven to be an excellent candidate for transplanting after germinating: because beets seeds are produced in a round hull of 2-4 seeds, they are a particularly good candidate for germination/thinning in individual potting cells. The root system will hence grow more densely intact within the potting medium, and will suffer far less, if at all, than if up-rooted from a open garden plot. If early growth has been possible in an outdoor environment, then you can transplant directly into your garden bed; otherwise, follow the typical rules for the process of indoor-to-outdoor ‘hardening off” before transplanting. In your situation, of having planted seed directly to your garden, the advice would be to scissor-thin your existing crop, and also as you asked, definitely try to mitigate sun-scorch or drought, and hopefully your beet crop be healthy and delicious!
Here is a very informative link to the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) online data service regarding transplanting from trays.