The Portabella Kit

January 9, 2009
For Christmas Jay's mom gave us a kit for growing portabella mushrooms. There's an interesting story behind the noble portabella. It is actually the same species (agaricus bisporus) as the common white button mushrooms that are sold in stores everywhere, and under normal growing conditions the mushrooms come up white and smooth and moderately sized. But occasionally commercial growers were dismayed to find a large, brown, rough-textured variation that could not be sold because customers wanted what they were used to. That is, until some marketing genius gave them a nice sounding name and showed that these new "portabella" mushrooms could be grilled, baked, broiled and generally cooked in more robust ways than their pale siblings. Now this once-unsaleable product commands a premium price. It illustrates the most powerful equation of marketing:  defect = feature.

The kit comes in a cardboard box, with an inner plastic bag filled with "mushroom compost" in which the fungus is already growing.

It will remain relatively dormant until you activate it by adding water. The procedure is to mix about 2 cups of peat moss, included in a separate bag, with 1 1/2 cups of water and then spread the mixture over the top of the compost. This casing provides an environment where the fungus will produce its fruiting bodies, i.e. the mushrooms we eat, and the water soaks down into the compost to encourage the mycelium to start fruiting. We activated the kit a week ago (January 2nd) and kept it in the basement, which is around 66 degrees. It is starting to show signs of life on top:

The white fuzz is the mycelium starting to grow up through the casing from the compost below. Here's a close-up of it:

Looks yummy, huh? Actually it smells good, sort of an earthy mushroomy smell. Soon it should start sending up little baby mushrooms that will grow to edible size. All we have to do is keep the top moist, keep the cats out of it, and eat them when they get big enough (the mushrooms, not the cats).

January 14, 2009
Near the edges of the box it's starting to look like little mushroom noses poking up:

It's not clear whether these are actual mushrooms starting to form, or just the mycelium growing upward in a more solid form.

January 16, 2009
The buttons are getting bigger and they're definitely looking like they'll turn into actual mushrooms. The scale is a little different between these two pictures so they're not as much larger as it might appear but they're definitely growing. You can also see some water droplets on the side of the plastic, from when I misted them this morning. Each morning I give them a light misting with a plant sprayer, as recommended in the instructions, to keep the casing moist but not wet.

January 18, 2009
They have grown to the size of a quarter now, and they're starting to get a cool crackled texture on top. Aside from the two main ones in this photo you can see some smaller buttons forming just above the quarter.

So far all of the mushrooms are growing at the edges of the box. Here's a shot of another cluster with a big lop-sided mushroom forming:

January 20, 2009
Counting all the little buttons that are forming, there are now about 20 mushrooms sprouting all around the edges of the box:

January 22, 2009
The larger ones are now 3 inches across and ready to harvest:

January 23, 2009
This is our first harvest, which weighed 12 ounces and made a delicious mushroom quiche. It was followed by a 7-ounce harvest the next day for a total of 19 ounces in the first crop:

The mushrooms pretty much matured all at once, so after harvesting them the box looked about the same as when we started out. According to the instructions, we should get another large crop in a couple of weeks followed by several smaller crops.

January 31, 2009
The second crop has started to grow, and it looks like it will be more uniformly distributed instead of just around the edges:


This page was updated on Wednesday January 11, 2017