Mushroom soil is the substrata used in commercial mushroom growing. It is sold after the mushroom crop is harvested. Mushroom soil can contain a variety of materials and varies from lot to lot.
It is usually steamed, pasteurized and partially composted, and may contain hardwood dust, coconut coir, vermiculite, peat moss, rice, cottonseed hulls, soybean and canola meal. Also, wheat straw, gypsum, and manure, usually horse or chicken. It is inoculated with the fungal spores and allowed to grow mushrooms.
Mushroom soil available to gardeners is equally variable. The product can be sterilized before sale to kill the mushroom spores, which means that it will also lack the microorganisms we like in our soil, This can be resolved by re-inoculating the soil with something like compost tea or mixing in regular compost. Unsterilized soil will contain some mushroom spore and will grow a few mushrooms.
The soil will be low in readily available nutrients, since that is what the mushrooms fed on. It will however, gradually break down, and can be considered a slow-release fertilizer.
Another concern is salts, as the mushroom soil may have a higher than usual salt content and may damage salt-sensitive plants. This can be alleviated by purchasing the soil in the fall or winter and allowing it to weather until spring.
Mushroom soil has a variety of good uses in the garden:
It makes a good soil amendment, adding organic material to the soil that improves the texture and water retention of the soil. It is a good addition to heavy soils. Note that this ability can be a problem, as the soil may retain too much water, so use with restraint — 25% mushroom soil to 75% soil or potting medium.
The soil is also a good top dressing for lawns, providing some slow-release nutrients.
Mushroom soil can be used as a mulch. Its low nutrient content dissuades weed growth and can be scratched into the soil later to improve structure. Used as a mulch, it may also discourage birds from eating newly sown seeds. The moisture retentive tendency will keep the seeds moist until they germinate.
Some sources indicated that mushroom soil can be used as bedding for vermiculture containers.
For additional information, see the Penn State fact sheet on mushroom soil (extension.psu.edu/spent-mushroom-substrate).
Weeds
This time of year, I get a lot of requests to identify weeds and I do my best to comply. But I sometimes wonder if knowing is all that essential. A weed is just a plant growing in the wrong place, and while it is necessary to identify those that can hurt you — poison ivy, oak, sumac, water hemlock, giant hogweed — most are just very annoying. Unlike insects, a weed is something you definitely want to get rid of.
Insects can be non-damaging or even beneficial, and should be identified before you attempt to get rid of them. Here, I like to mention the slaughter of all caterpillars without identifying if they are something harmful, like a hornworm or something relatively benign, like a larval swallowtail. Butterfly gardens will not exist without caterpillars, and using a grub control method such as Bt may be part of the reason you have few butterflies in your garden.
So, in general, my advice is to look at the plant and identify it if possible. But in any case, observe how it spreads (seeds, rhizome, etc.), and how it grows (shallow root, long taproot) and then adopt an appropriate control method. Note that I say control, not eradication. It is almost impossible to totally eliminate weeds. I’ve seen some in the best-groomed display gardens.
First and foremost, don’t allow weeds to go to seed. Many plants produce hundreds and even thousands of seeds. So getting the flowers or seed heads early is essential in any weed-control program.
Second, weeding is a perpetual task so don’t expect to get rid of anything in one weeding session. Even the most diligent weeding may leave a small portion of the root or stem, or a few errant seeds that can regenerate or sprout. Consider trying to control mint. Even a small stem or root portion can re-establish the plant.
A horror story from my early gardening career is when a neighbor decided to be helpful and roto-tilled one of my garden beds. While I grew tomatoes in it, there was also a corner dedicated to mint. My mother, a British war bride, loved to make a mint sauce to go with her lamb roast, so I grew a small plot for her. Anyway, after he tilled the area — without removing the growth already there, I had a large bed of mint and had to relocate my tomatoes to another area.
I prefer not to use chemical weedkillers for a variety of reasons: potential toxicity to the environment, the non-discrimination of many weed killers (actually vegetation killers), retention of chemicals in the soil affecting later growth, the potential to use inappropriate chemicals on food crops. Therefor, I try to limit usage to horticultural vinegar, although I do admit to using something a bit stronger on some especially noxious plants.
My flameweeder is one of my favorite weed-control devices. It works by exploding the plant cells, which kills the plant, not burning them up, and is best used on small weeds or those recently watered. It must be used with caution.
Another horror story is when we first moved to our current home and had a contractor and several workers at the house for the first month or so. The contractor, disliking idle workers, ordered one to use the weeder on the stone driveway. Taking initiative, the worker weeded not only the driveway but also some mulch-covered beds. Several hours later, we smelled smoke and found the mulch in one area smoldering.
Some plants can be killed by just continually cutting them back until the roots can no longer support new growth. I find this works reasonably well when unwanted tree seedlings get established and are too large to just pull out.
Sue Kittek is a freelance garden columnist, writer, and lecturer. Send questions to Garden Keeper at grdnkpr@gmail.com or mail: Garden Keeper, The Morning Call, PO Box 1260, Allentown, PA 18105.
Week in the Garden
Planting
Plant a second or third crop of snap or pole beans, radishes, carrots.
Sow small sections of crops like beans, radishes, lettuce, and spinach at regular intervals to create a longer harvest.
Set out tomatoes, basil, eggplant and pepper transplants as weather and soil warms.
Start seed for: Baby’s breath, cosmos, zinnias, salsify, eggplant, summer squash and winter squash.
Direct sow: Corn, okra, and rutabaga.
Continue sowing: Snap, bush and pole beans, cantaloupe, melons, cucumbers, rhubarb, summer and winter squash.
Plant or pot up summer bulbs and tubers such as dahlias, cannas, calla lilies, and caladiums.
Plant bare root trees and shrubs.
Make sure the soil is dry enough to work — don’t dig or plant in mud.
Buy annuals for containers, annual garden beds and to fill in bare spots in perennial or shrub beds.
Seasonal
Stalk tall flowers and provide supports for vining plants.
Cut back boltonia by half the size of the plant.
Cut Joe-pye weed back to three feet tall.
Cut back candytuft to encourage bushiness.
Shear back woodland phlox (P. divaricata)
Deadhead sea thrift (Armeria), centaurea, centranthus ruber, dianthus, fringed bleeding heart (Dicentra exima), hardy geraniums, bearded irises, red-hot poker (Kniphofia uvaria/tritoma), catmint (Nepeta), herbaceous peonies, oriental poppies, pincushion flowers (Scabiosa).
Fertilize Siberian irises, summer phlox (P. paniculata) and Shasta daisies with a light application of balanced fertilizer
Divide spring blooming perennials after they finish blooming.
Cut back peony flower stems as the blooms fade. Allow the greens to grow until fall, then cut them back to the ground.
Clip back iris flower stems as the blooms fade; divide plants in crowded beds.
Pinch back helenium, chrysanthemums and asters to promote bushy growth and more flowers. Continue to pinch back new tips at two-week intervals until early July.
Ease out your plants that wintered over inside. Start with an hour or so on a warm day and increase outdoor time until the nights are regularly in the 50 degrees F range before leaving them out for the season.
Visit nurseries as they open for inspiration as well as new plants.
Shop for summer bulbs as well.
Apply a top dressing of compost to lawns and beds.
Test soil for new beds. Retest soil in poorly performing areas or those that haven’t been tested in the last 3-5 years.
Apply spring and summer mulch, two to three inches deep and placed a few inches away from foundations, tree trunks and other plants.
Fluff mulch and add more if necessary.
Apply corn gluten-based weed control in the garden and establish a schedule for reapplication, usually at four to six week intervals.
Lawn
Keep newly seeded or sodded lawns watered; supplement rain in weeks where it is less than an inch.
By mid-June:
Apply spring fertilizer treatments.
Apply pre-emergent crabgrass control in the next few weeks.
Fill in holes and low spots in lawn.
Chores
Check seed inventory for second or later plantings or for late crops and fall planting.
Inventory and restock seed starting and potting supplies.
Clean, disinfect and store pots and trays used for seed starting and transplants.
Water any recent plantings and containersany time we experience a week with less than an inch of rain.
Fix damaged screens and garden hoses.
Note damaged caulking around doors and windows.
Dump standing water and remove anything that may collect rainwater to help control mosquito populations.
Provide deer, rabbit and groundhog protection for vulnerable plants.
Reapply taste or scent deterrents.
Clean and fill bird feeders regularly.
Clean up spilled seed and empty hulls.
Dump, scrub and refill birdbaths at least once a week.
Consider setting out nesting materials if you have them.
Clear gutters and direct rainwater runoff away from house foundations.
Tools, equipment, and supplies
Store winter equipment and replace or repair as needed.
Check spring/summer equipment — repair or replace damaged or worn-out tools.
Check power tools and mowers and send for service if needed.
Safety
Clear lawns of debris before mowing and make sure pets, children and others are well away from the area being mown.
Store garden chemicals indoors away from pets and children. Discard outdated chemicals at local chemical collection events.
Photograph storm damage before clearing or repairing for insurance claims and file promptly.
Anytime you are outside and the temperatures are about 50 degrees F or warmer, watch for tick bites.
Use an insect repellent containing Deet on the skin.
Apply a permethrin product to clothing.
Wear light-colored clothing, long sleeves, hats and long pants when working in the garden.
Stay hydrated. Drink water or other non-caffeinated, nonalcoholic beverages.
Even in cold weather, apply sunscreen, wear hats and limit exposure to sun.
Wear closed-toe shoes and gloves; use eye protection; and use ear protection when using any loud power tools.
