The first flush off a Blue Oyster block usually comes as a surprise to a first time grower, especially since Blue Oyster can begin pinning in as few as five days under the right conditions. One morning there is nothing but a faint bump on the surface of the block, and within days there is a cluster of steel blue caps reaching toward the window.
That first harvest is the one most home growers photograph, but the real question most people ask Foxfire Mushrooms after that initial cut is simple: how many flushes can you get from a mushroom grow kit before the block is done. According to Foxfire’s own published growing guidance, most kits produce two to four flushes total, with the first flush almost always the largest and each round after that getting smaller.
Quick Facts — Typical flushes per kit: 2 to 4 – Blue Oyster flushes: 2 to 4 – Lion’s Mane flushes: 2 to 3 – Rehydration after harvest: 4 to 8 hours in cold water – Rest period between flushes: 5 to 7 days – Foxfire’s current grow kit lineup: Blue Oyster, Lion’s Mane, and Pink Oyster
A flush is one complete wave of mushrooms growing, maturing, and getting harvested from the same fully colonized substrate block. It is not one mushroom or one cluster necessarily, it is everything that comes up and gets cut in a single round before the block rests again. Inside every Foxfire kit, that block starts as sterilized hardwood or supplemented sawdust that gets inoculated with clean mushroom spawn and allowed to fully colonize before it ships, so what a home grower opens is not raw sawdust but a solid mass laced through with mycelium, the vegetative growth of the fungus that eventually produces the mushrooms.
The mycelium itself does not disappear after a flush. It stays alive inside the block, working through whatever moisture and nutrients remain in the substrate. Every flush draws on that same limited supply. Once enough of it has been used, the block runs out of what it needs to build another full round of fruit, which is part of why the yield curve drops off with each flush.
By the time a kit ships from Longmont, the mycelium has already fully colonized the block, meaning it has spent weeks building up dense tissue and storing moisture and nutrients in the process. Because the block is fully colonized and well hydrated when it first enters fruiting conditions, the first flush is typically the largest one a kit produces. After that harvest, some of the block’s available moisture and nutrients have been used, so later flushes are generally smaller.
Foxfire recommends giving a block five to seven days of rest in its fruiting environment before expecting the next flush, and advises against giving up on a quiet block too soon since the mycelium may simply be regenerating. Before that rest period starts, the block needs to be rehydrated. The instructions call for filling the grow bag with cold tap water, submerging the block completely, letting it soak for four to eight hours, then draining it fully before returning it to fruiting conditions. Skipping that soak is one of the more common reasons a kit only produces one usable harvest even though the mycelium had more to give.
Humidity and air exchange matter just as much as the soak. Foxfire’s own growing guidance targets 80 to 95 percent relative humidity right at the open cutting site, along with a quick fresh air exchange, gently fanning the growing area or opening the humidity tent for 30 to 60 seconds twice a day to clear out built up carbon dioxide. A block sitting in a dry room with no air movement will stall out no matter how well it was soaked.
It does, and Foxfire’s current grow kit lineup, Blue Oyster, Lion’s Mane, and Pink Oyster, each behaves a little differently. Blue Oyster is the workhorse of the three, an aggressive colonizer that typically produces two to four flushes and can pin in as few as five days in a cool space between fifty five and sixty five degrees. Lion’s Mane is the more forgiving option across a wider temperature range, usually giving two to three flushes with the first pins taking seven to fourteen days to appear. Pink Oyster is the fastest fruiting of Foxfire’s oyster kits and performs best in warm rooms between seventy and eighty five degrees, though it can stall out if the room drops much below sixty five degrees, so it tends to reward a warm kitchen more than the other two.
| Feature | Grow Kit | Grain Spawn |
| Typical flushes | 2 to 4 | Depends on substrate used |
| Best for | Beginners wanting a block that is ready to fruit | Growers ready to inoculate their own bulk substrate |
| Setup effort | Minimal, open and mist | Requires mixing and inoculating substrate |
| Starting price | $27.99 per kit | $24.99 for a 3 pound bag |
| Typical total yield | About 1.5 to 3 times the block’s dry weight in fresh mushrooms | Higher, since one bag can inoculate several substrate tubs |
| Contamination risk | Low, block arrives fully colonized and ready to fruit | Moderate, depends on technique during transfer |
A grow kit is built for someone who wants results without managing sterile technique. Grain spawn is a better fit once a grower is comfortable inoculating their own substrate and wants to stretch one purchase into several fruiting blocks rather than relying on flushes from a single finished kit.
After about three flushes, blocks often show signs of exhaustion: slower pinning, smaller clusters, and greater risk of contamination at the exposed harvest points. At that point, composting the block is the right move rather than continuing to mist it and wait. Used blocks make excellent additions to a garden bed, since the leftover mycelium continues breaking down organic matter even after fruiting has stopped.
The biggest lever a grower actually has control over is timing the harvest correctly, since cutting mushrooms too late can weaken the flushes that follow. For Oyster varieties, the right window is when the caps are fully formed but before the edges start to wave and flatten. For Lion’s Mane, that window is while the spines are well developed but the body is still firm and white, since both the flavor and the block’s remaining energy decline once it starts to yellow. Harvesting promptly at that stage, rather than letting mushrooms sit past their peak, tends to encourage a stronger next round instead of draining the block for nothing.
Tracking flush counts across a full grow cycle is the best way to learn what a given species can realistically give, and it helps to go in expecting the second and third flush to be a bonus rather than a guarantee. With good technique, two to four productive flushes typically add up to roughly one and a half to three times the block’s dry weight in fresh mushrooms, which is a meaningful amount of food from a single kit. Every order over seventy five dollars ships free, every grow kit ships with a live arrival guarantee, and Foxfire backs each kit with a thirty day money back guarantee if it arrives contaminated, damaged, or fails to produce pins under normal conditions.
The best way to actually know how many flushes a kit can give is to run one through a full cycle and pay attention to what the block is telling you at each stage. Foxfire’s current lineup, Blue Oyster, Lion’s Mane, and Pink Oyster, all arrive fully colonized and ready to fruit, with clear instructions for the soak and rest routine between flushes. Shop Foxfire’s current Blue Oyster, Lion’s Mane, and Pink Oyster grow kits and put the next flush to the test.
Most kits produce two to four flushes total, with the first flush typically the largest. Blue Oyster tends to land on the higher end of that range, while Lion’s Mane usually produces two to three.
A dry block, unsuitable fruiting conditions, contamination, or skipping the cold water soak after the first harvest can all cause a kit to stop after one round.
New pins can appear after the block is rehydrated and returned to stable fruiting conditions, but the timing varies by species and growing environment.
It happens occasionally, especially with vigorous Blue Oyster blocks, but by that point the block is usually showing signs of exhaustion like slower pinning and smaller clusters, and most growers find it is time to compost rather than push for another round.
Yes, later flushes tend to produce smaller caps and thinner stems since the block has less stored energy to work with. The mushrooms are still perfectly edible, just less substantial than the first harvest.
Fill the grow bag with cold tap water, submerge the block completely, let it soak for four to eight hours, then drain it fully and return it to fruiting conditions before the next rest period begins.
Once pinning consistently slows and clusters keep shrinking, composting the block is the best option. The residual mycelium continues to benefit soil health even after its fruiting days are finished.
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