Complimentary Blueberry Juice

It occurred to me that I had never taken a soil temperature reading, so I’m going to start and see what we find. We use these row covers quite extensively, but I’ve never measured just how much they increase the temperature – and specifically soil temperature – underneath. We have also never applied mulch in this way before, and with no sunlight hitting bare soil, we expect the soil temperatures to be a little bit lower.

Whether or not it makes a great deal of difference if row covers are put out prior to seeding or transplanting, or if the soil is covered or uncovered, is what I’m trying to find out.

It would just help to be aware for my own specific context approximately what soil temperatures can be expected in different times of season and different types of bed configurations we use in our system (bare soil, mulch, row covers, or a full canopy).

Last season we had a lot of difficulty with cold soils affecting germination rates. As a response we are instead putting row covers out first for a number of days prior to seeding to warm the soil up.

There were two initial temperatures taken for our first baseline. From one of the beds underneath the cloth in this photo, and another from a bed with no soil cover at all, receiving direct sunlight.

Temperatures were taken around 1pm. The air temperature was 10C. The top 5cm of bare soil was at 14C, while under the mulch it was just 5.5C. That’s quite a difference, however beyond 5cm was nearly identical at around 4C +/- 0.5C.

We will leave these covers on for at least 7 days and take a new reading (and probably put out more covers).