How Long Does a Mushroom Flush Last? (Solved & Explained!)

Once a mushroom starts “pinning,” or growing tiny buttons of primordia that are the immature beginnings of mushrooms, the fruits should be ready for harvest within a week. It is important to harvest the mushrooms during the flush at the peak of ripeness to avoid the textures and flavors that accompany overripe mushrooms.

The rest of this article will go into how to determine when a particular variety of mushrooms is ready for harvest, what will happen if you wait too long, how to know that the flush is over, and tips on finding wild mushrooms during a flush.

When Does the Flush Start?

Once the mycelium is mature, and has fully inoculated the substrate, it will grow tiny bumps along the surface called primordia. This is the beginning of the flush, which will take about 3-7 days for most varieties of mushrooms to grow to peak ripeness.

When Does the Second Flush Start?

The primordia of the second flush are sometimes already growing by the time you’re ready to harvest the first flush. For some mushroom varieties, the first and second flush tend to overlap, so you will harvest two flushes of mushrooms within 7-14 days.

More often though, another flush will happen around two weeks after the first, producing a slightly smaller crop than the initial one. If you are lucky enough to get subsequent flushes, they will produce smaller and smaller harvests of fruit until the mycelium is exhausted.

How Will I Know When To Harvest?

Every mushroom type has specific things to look for to determine how ready the fruits are for harvest, but generally, mushrooms are ready to be picked once the caps have turned upwards slightly. 

Harvesting slightly too early in the flush is better than harvesting too late because the fruits will be more tender. Picking mushrooms too late in the flush often results in a fruit that is full of flavor, but slightly tough and more likely to spoil.

Oyster Mushrooms

Harvest when the cap of the largest mushroom flattens or turns upwards slightly, about 3-5 days from pinning. This type can turn from ready to overripe in a single day, and waiting too long can result in the release of spores or a dried-out fruit with off-flavors.

Shiitake Mushrooms

Harvest when the caps are still slightly turned downwards, but the gills are visible, about 3-7 days after pinning, depending on the weather. When the edges are upturned, the fruits are still edible, although they will be overripe and will not last as long in the fridge.

Portobello Mushrooms

This variety has the longest flush of all since you can harvest crimini mushrooms about 5 days after pinning, or wait until they grow to full-sized portobellos 10 days or more after the first primordia. Make sure to harvest just before the edges flatten to avoid a woody texture or the release of spores.

Maitake (Hen-of-the-Woods) Mushrooms

This variety takes longer to grow, and your kit will not flush for up to a year after inoculation. Because of how difficult this variety is to grow at home, it is often foraged in forests or woods.

Harvest when the mushrooms are 1-2 inches long and don’t be tempted to wait until they are bigger. This variety is tender and tasty when young, but will be tough and produce a foul smell if you wait even a day too long to pick them!

How Long Do Wild Mushroom Flushes Last?

Flushes for wild mushrooms typically last for a week or less, just as for mushrooms grown from farms or in kits. If you happen to pick a wild mushroom that is dried out and past its prime, be sure to crumble it up and leave it where you found it so that the spores can become next year’s crop!


These unusual mushrooms with their honeycomb-like caps are in the decline in the wild. To increase the chances of finding a morel during a flush, many people have started cultivating their own morels in shady and moist backyard plots, as well as finding them in the woods.

Morels flush and are ready for harvest for up to a week during their season March through May. Pick them when they have just started to darken and check to make sure they are not dried out.


These wild yellow, orange, or black mushrooms take about 2 weeks from pinning to full flush during their season in August to mid-September. Harvest only the larger ones with visible wrinkles or false, forked gills and use them within 48 hours at room temperature or up to a week in the refrigerator.

Puffball Mushrooms

Puffballs flush for a few weeks in cool weather, generally between August and October. The ripe fruits are obvious because they can grow larger than a volleyball and are creamy-white when edible, although they are still delicious when picked and eaten small.

When a puffball is not white on the inside, or has begun to turn brown on the outside, that means it’s ready to spread spores and is no longer edible. Another indication that you waited too late in the flush to harvest is an excessive amount of cracks in the puffball.

What Happens If I Wait Too Long?

Once the flush is over and the fruits are overripe, they will start to dry out and release spores. Depending on the type of mushroom, the fruit may still be edible, but it may taste bad, have a tougher texture, or will rot quicker than it would if picked at the correct time.

Can I Extend a Mushroom Flush?

Unfortunately, there is no way to extend the amount of time a mushroom is flushing. You can try to encourage an additional flush, or give the mycelium a fresh substrate to get more flushes, but you will have to pick your fruits at the ideal time during the flush and refrigerate them if you want to prepare them later.