a small leaf pile will destroy the grass underneath it quickly, but an even thicker snow pile that lasts for months throughout the winter seems to have no effect. Why?

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Editing just to say thanks to everyone who has contributed. The responses make perfect sense!

In: Biology

15 Answers

Anonymous 0 Comments

The moisture buildup, warmth, and lack of airflow kills the grass. Basically starts a mini-compost pile. Look up what happens when you cover soil with cardboard sheets.

[https://en.wikipedia.org/wiki/Sheet_mulching](https://en.wikipedia.org/wiki/Sheet_mulching)

I don’t agree with other comments here about leaves being acidic or lack of nitrogen in the leaves. It’s not like grass will die without a steady stream of organic N being fed to it, and composting leaves typically don’t have any substantial effect on soil pH (and the top leaves don’t decompose fast enough to have any effect at all).

Anonymous 0 Comments

Snow is white and your plant friends will still see the light and be able to breath, but they are sleeping now, so it’s not a big deal anyway.

Anonymous 0 Comments

The grass underneath dies from lack of sun.

Snow is mostly air and very light permeable.

I had a tabletennis table on my lawn one whole summer and all the grass in the shadow underneath was completely gone, while the one we were trampling while playing was doing fine.

Anonymous 0 Comments

If they’re sitting on the same pile for ages, this will first of all, restrict oxygen and sunlight to specified patch.

Second of all, the nutrients from the pile will scorch the ground underneath as it’s too concentrated!

Anonymous 0 Comments

The leaves give of antinutrients which kill the grass. Also, leaves block out light completely, whereas snow let’s lights through.

Anonymous 0 Comments

At least one part of it is that light can still pass through the snow, unlike the pile of leaves.

Anonymous 0 Comments

leave block more light than snow. snow lets a surprising amount of energy though mostly because un-compacted snow is very low density in made of transparent material ie ice and water, for instance if you get snow on solar panels the panels can still make some energy not much but there is enough light to also heat up the glass so snow falls off.

to make a long reply short the grass can still photosynthesize and its cold so it needs less light anyway

Anonymous 0 Comments

Anaerobic conditions under the leaves too.

Snow allows air in.

Fun fact, the MOST decomposition in the world happens in that tiny layer of water between the snow and the ground and not in the tropics as people think.

Anonymous 0 Comments

the composting process also hits non-dead things. imagine being covered in guts and gore and the bodies of a thousand fallen men, women and children, trying to survive for days and weeks on end without the slightest bit of air, fresh water or sunlight. all you can do is try and live from the corpsebile oozing down towards you.

exactly. i’d be more surprised if they DIDNT die, tbh

snow/winter makes plants hibernate and if that work for animals, then it cant be that hard for plants either, right?

Anonymous 0 Comments

Couple things at play here. In winter the grass is dorment so it is not trying to grow or absorb any nutrients. It doesn’t NEED the sun in winter. In fact the snow can help protect the grass. The snow is at a stable temperature just below freezing. Without the snow the grass can be exposed to MUCH colder temperatures and strong winds causing winter damage especially if the grass is tall and unmowed.

In fall the grass is still trying to grow so the leaves will block all the sun preventing any photosynthesis. Also if there is any moisture, the leaves will keep it from drying out so it’s just wet and dark underneath, great for disease and bugs to grow helping kill the grass faster.