mulch colour

 

hello,

in retrospect, i am thinking now that it ended up being unfortunate that we
mulched with horse poo, rather than (say) straw, just before a stint of
(unseasonal for the area) hot weather with almost no rain.

knowing that dark colours are likely to absorb heat & lighter colours to
deflect it, i've been putting straw round the veggies over the top of the
poo (but as my plants are pretty well spaced, most of the bed areas are
still pooed, rather than strawed).

when i walk into the veggie garden, anecdotally at least (i haven't measured
due to a lack of a working themometer at the moment!!) it is several degrees
hotter there than in general garden areas (where the larger plants would
ease the effect with shading, transpiration & all that stuff - but there are
no larger plants in teh veggie garden - it's just blindingly hot :-).
between the rows the grass is short & dry & therefore light-coloured, but
the throb of heat you experience walking in on a hot day is quite remarkable
nevertheless!

i can't recall any previous time in my fairly limited gardening experience
where i've noticed that i seemed (personally) to have created an inadvertant
heat sink like this. the garden in general, the veggie patch in particular,
is struggling with lack of water atm & it's just making me sad, really. i
haven't been getting good germination this spring/summer, nor good growth.
there are things i'm just not doing because i foresee that they would fail,
& i should just put it off until a cooler/wetter period starts up.

any thoughts or comments on mulch colour?
ta!
kylie

 

0tterbot wrote:

There is also the cooling effect of water evaporation.  Darker green lush
growth feels cooler than lighter dry growth because it is keeping cool by
evaporation.


In principle a lighter colour will reflect more heat but I doubt the
difference would be great.  It will still be fulfilling its main purpose of
insulating and covering the soil.  In any I case it would be better than
none.

You could always apply a thin whitewash of lime ;-)

David

 



well, that's what i was calling "transpiration". :-)


certainly! i'm not sure a few degrees' difference is even waht you would
call a "great" difference - and as i said i've not actually measured it,
just going by feel.


i could just concrete the whole lot over, even <g!>
kylie

 

0tterbot wrote:

Call it evapotranspiration then.  Which is what we have right now, due to a
hot north westerly.  Praying for rain for Xmas.

David

 

0tterbot wrote:

Funny you mention that.

I used to mulch with stable manure (mixed liberally with wood-shavings)
and it remains my favourite mulch to this day. Sadly, we no longer keep
horses, so I've had to revert to paddock-pickings (ie pure poo) to bring
home and rot. This feels *much* hotter to me than the shavings mixture.
I'd never discussed it with anyone before, but I think we've hit upon
something here.  Would it be worth investing in a bale of sugar cane
mulch to cover the poo thinly and (perhaps?) reduce the temp?

--
Trish Brown

Newcastle, NSW, Australia