Local Harvest Gardening

What's the difference between compost and mulch?

my understanding is that compost is material that is nutrient dense due to the decomposition of organic material and mulch is ground covering that can be either dead organic material that is typically nutrient deficient, or inorganic material such as rocks and landscape fabric.

Thermophilic compost can be used as a mulch as it will be a weed free covering on the ground but you really need lots of it and it is like gold. The industrial, waste reduction compost is not so full of life and will be seed free and maybe a good mulch. I use good home grown compost initially and then cover with Leaf mulch to keep the moisture in the ground and let the gold below help all the biology. In my home garden, I will remove the mulch layer and spread a small layer of new compost when doing a bed transition to next succession planting. Plant seedlings and re-spread the mulch around the plants. If it makes it over winter, I reuse it or it gets added into the compost piles and start again with fresh mulch.

I also use a lot of the chipped woody material I generate from yard trimmings to my perennial beds as they do not get much working so just cover to keep the soil covered and weeds down. Woody materials on top will not rob nitrogen if it stays on top and does not get mixed in. The cover keeps the soil moisture up and any weeds that do show their head are easily removed from the soft soil beneath.

troy wrote: ↑Wed 29-Dec-2021, 06:44 my understanding is that compost is material that is nutrient dense due to the decomposition of organic material and mulch is ground covering that can be either dead organic material that is typically nutrient deficient, or inorganic material such as rocks and landscape fabric.

I would add to your compost definition has a good fungal:bacteria ratio for the crop you want to grow and has predators present for good nutrient cycling.

For mulch I would say ultimately a mulch would be plant material free of seeds (for ease in the long haul) and be something that will feed the soil biology below. Rocks will prevent any growth and plastic will kill anything that does germinate below and prevent weeds but will not feed the soil biology after the worms have finished munching on any of the organic materials that was not fully broken down prior to covering. Plastic will prevent compaction and erosion from rain but not allow the water to easily get into the soil either. The main goal of a mulch it to cover the soil surface, prevent erosion and compaction in rain events and also insulate the soil which helps the soil retain water by reducing sun exposure and evaporation and also keeps the soil from getting too hot in the sun.

thx for the comprehensive descriptions!