How often do you add compost to garden beds? Ive been adding compost every three years but not sure it's necessary since I also add mulch.

I doubt that it's possible to add too much.
When I have a compost pile, and plants grow in the pile, or next to it, they always outperform the rest of the garden.
I think adding compost as often as possible might be a better plan than the current one of waiting 3 years.

It's hard to go overboard on compost.

sj6x said: How often do you add compost to garden beds? Ive been adding compost every three years but not sure it's necessary since I also add mulch.

It depends on a few factors such as the quality of the soil, the type of plants grown, and the climate. I usually add compost every three years, but it's not a hard and fast rule.
If you notice that the soil is becoming depleted or the plants are not thriving as well as they should be, then add compost more frequently, perhaps every two years or even annually.

Every two to three years? I'd be gardening in pure rock dust if I let it go that long. Wind, sun and freezes deplete the organic matter in topsoil, along with plants, of course. Some plants, like cactus species and others that like barren xeric conditions prefer lean gritty soil, but if you're growing veggie crops or most garden ornamentals, applying compost 2 times a year is reasonable. So many variables, it's hard to properly answer a question like that without more information and specific conditions.

My soil is so sandy, it's hard to add enough OM to keep it from drying out very quickly.

As frequently as you can. I make a LOT of compost and everywhere I can. I could use 10x as much. I trench compost in beds, sheet compost in same, have about 80 gallons in barrels of mushroom compost, and have four bins that get fed constantly. I apply the bins once a year to the beds. But I'm applying directly to beds every week. I get a lot of eggshells (about 15 cases of 15 dozen eggs a week), coffee (about 5 gallons of spent grounds a day), and kombucha spent leaves and SCOBY. I use roughly 300 paper leaf bags full of leaves a year. Woody stems usually sit hidden in at the bottom of compost bins for a few years, buried in bins, or hidden behind plants.

Basically, I don't feel like you can have to much organic matter. Neither does the organismic community my soil.

I grow a lot of sedum and other plants that grow in well-drained "poor" soil, and do not require a lot of fertilizer. In my case, adding compost might be a negative. One thing I did note in my sedum areas is that leaves fall on them and then decompose, and go to the root zone area-- from then they further decompose until next season. So-- they are adding compost on their own but just scant amounts. Just the devil's advocate here, saying not all plants want a lot of compost.

That is true, some plants just rot in rich "black gold" garden soil.

I add compost when I fork the soil over and can see there's not much compost left in the bed. For whatever reason, some of my beds have more bio-dynamic activity than others: the churning of worms and other soil denizens.

A couple years ago, as an experiment, I added shredded fall leaves (not leaf mold) to a few of my beds with a thin layer of compost on top of the leaves and straw mulch on top of that. I left these beds fallow and by late summer the leaves and compost were 85% broken down into the soil. These beds must have been a hot bed of action. lol

I find the addition of compost to be an on demand situation in my garden.