Good to mulch in fall

Green thumbs up

to blanketing the garden with mulch in fall. It's customary to do this work in spring but there are good reasons to follow Nature's lead in applying all that organic matter in fall. (How much mulch will you need? Check the Mulch Calculator.) We count seven advantages but just three drawbacks:

 

There is so much free mulch in fall. This year, let's use it.

Positive aspects:

1. It's a damper not only on weed seeds that would germinate in spring but to the "winter weeds" as well -- creeping speedwell, tall rocket and others.
2. It provides some protection to plants against the big temperature swings that can kill roots in bare soil as the season changes.
   Follow their lead: Northern botanical gardens mulch in fall (Here, Olbrich Botanical Garden in Madison, Wisconsin)
   
3. Mulch will be there to cushion the soil against the pummeling of winter rain. Those icy drops can leave a layer of water-repelling clay on the surface of what had been crumbly soil.
4. We gardeners have more time available in fall and we're not racing against plants on the rise.
5. We'll be able to sit back and enjoy the emerging show in spring, with a good portion of the work already done.
6. We don't have to be so careful in fall as in spring, to avoid covering perennials' crowns. Young shoots that can be overheated or rotted by trapped moisture if covered after they begin growth in spring, are not there to be hurt in fall. When those shoots do develop in spring they'll do it under cover with every cell receiving cues from day one that say, "Stay tough, you're still underground."
7. There is a lot of free mulch around in fall. A layer of autumn leaves is fine mulch on its own but if that look doesn't please the eye they can be the underlayer that allows us to use much less purchased mulch as a veneer layer -- we can get away with less that an inch of shredded bark over the top of leaves.

Below: Sometimes we shred the leaves before using them as mulch in fall but most of the time we rake 'em up and toss 'em on. Does it hurt the perennials to have 5 or 6 inches of leaves over them in fall? In 30 years of doing this we've seen far more good come of it than bad. The bad: Sometimes in spring we have to poke at hard clumps of leaves that are rising like hats as plants beneath push up. Most of the time, only 1-2 inches of leafy matter remains as mulch by spring and that's a perfect number.

Negatives:

1. There is some chance that fresh mulch in fall will provide homes for voles -- shrub- and tree bark chomping meadow mice. The rodents won't appear just because there is mulch, however. It's an issue to be taken into serious consideration where vole problems have already existed during the year. Traps or poison baits are necessary there, early mulch or not.
2. If we don't get all our dividing and moving around done at this end of the season but we do spread mulch in fall, the mulch will be in the way and need raking-out in spring around the plants still "on deck" for division.
3. The mulch may break down and have to be topped up in spring. But then, we don't really count it as a bad thing that gentle natural processes churned some extra organic matter into the soil!

Leafy part of fall clean up

Below, left: One day in early October we realize "it's about time to wind down."
Below, right: So by mid-October we come to the time to yank out, divide, and replace.

Below, left: However much organic matter we take out -- such as a wheelbarrow full of daylilies and their roots -- we put back that much compost. This is worm castings from a bait worm company.
Below, right: This creates some bare space.

We're happy if, when we finish in fall, every bare space has leaves on it, and all the plants, too.

For more about what we do when in fall, download our presentation, The Art of Fall Garden Clean-up.