On Jun 14, 11:41?am, wrote:
On Wed, 13 Jun 2007 18:03:42 -0700, Sheldon wrote:
Actually anything that impedes evaporation keeps the soil from
cooling... evaporation is what cools soil, the more air circulation
the more the soil cools.

....... true

Most mulches (unless highly reflective andporous) act to keep soil warmer... dark mulches can kill plants by
causing roots to literally cook.

........... up here in zone 5 mulch is used to keep the soil cool.

You not but a few hours ago claimed you reside on the Alaskan
tundra... and grow fruit trees there.

tomatoes are never mulched until the soil temp is high enough that it
wont impede growth. and mulches are used to moderate soil temp,
including keeping the soil cold under fruit trees in spring so they
wont blossom out to soon. Ingrid

It's scientifically impossible for mulch to cool soil, mulch (any
mulch) can only act to warm soil. Mulch absorbs radiant energy from
the sun, transfers heat energy directly to the soil, and insulates to
retain heat... when soil temperatures become too warm then it's best
to remove mulch and/or shade the area from direct sunlight with some
sort of suspended light diffuser, such as opaque plastic sheeting that
permits lots of aeration. Mulch does not add shade... any mulch
suspended above the soil is no longer mulch, then it becomes a
parasol. I've now concluded that you are not any kind of dr., perhaps
of bs.

Btw, tomatoes do not grow during daylight, tomatoes are in the
nightshade family, they absorb energy during daylight and only grow at
night time. Tomato plants of any age love hot days and hot nights...
tomatoes don't do well when nights are cool.