Start Seed Planting Indoors with Oven-Sterilized Soil

Start planting seeds indoors now to take advantage of the entire growing season. Some flowering plants may need to be planted 6, 8 or even 10 weeks before the last frost date for your area. Perennials may not have enough time to flower the first year unless you help them out by starting their seeds early.

Any container can be used for starting seeds that provides at least two inches of soil depth and that has drainage holes. Old containers, flats, cut-off milk jugs and plastic bottles are just fine, provided that you clean them with warm, soapy water. If you want to be really careful, take a few extra minutes to disinfect your containers with a 10% bleach solution (1 part bleach plus 9 parts water).

Put your soil in the containers to a depth of at least two inches. The kind of soil that you use for starting seeds does make a difference. Regular potting soil is too dense and allows for little water drainage. Potting soil or dirt dug up from your garden will work fine if you add vermiculite and perlite in approximately equal parts. As an alternative you can use equal mixtures of garden soil, sphagnum peat moss and sand. The vermiculite, perlite and sand all serve the purpose of increasing drainage, lightening the soil and allowing for good oxygen exchange.

Actually, potting soil isn’t even a requirement. You can mix equal parts of vermiculite and perlite, or sphagnum peat moss and sand, instead. Going a different route, you can try rock wool for starting your seeds. Rock wool is used for plants in hydroponic setups and may not be easily found in your local gardening center.

Sterilization of the soil can improve results significantly. Some folks opt to purchase the more expensive, commercially prepared seed starting potting mixes, which are available in specialty garden shops. Commercially prepared soils are conveniently sterile for starting seeds, but more expensive than doing it yourself.

Sterilizing soil basically involves heating the soil long enough to destroy the disease-causing bacteria and fungi, but not too long for toxins to develop in the soil. You can do it at home in your conventional oven, too.

Porous containers, like clay pots, can be sterilized in the oven the same time as your soil mixture, but make sure to disinfect your clay pots first with a 10% bleach solution.

We can get by without sterilizing the soil, but if you want a better result bake the covered soil at 180-200 degrees for about 30 minutes.

Follow these steps for oven sterilization of soil and containers:

  • Heat oven to 180-200 degrees F.
  • Use metal containers or clay pots to hold the soil for sterilizing. No plastic containers.
  • Fill containers with moist soil mixture no deeper than 4 inches.
  • Cover containers tightly with aluminum foil.
  • Heat at 180 degrees for 30 minutes. Use a meat thermometer poked into the soil.
  • Do not let temperature go over 200 degrees.
  • Allow the soil and containers to cool to room temperature.
  • Leave the foil on the containers until you’re ready to use the sterilized soil.

While the oven is baking your soil, you’ll want to open a window or turn on a fan to get rid of the odors being released!

You can use the microwave for sterilizing small batches of soil but you’ll have to use plastic containers and not metal ones or aluminum foil. The key here is to hold the temperature at 200 degrees for 20 minutes, so if you have a programmable oven you’re good to go. Oh, poke a hole in the lids of your plastic containers to allow steam to escape while the soil is getting zapped.

Now that your soil and containers are ready, let’s plant seeds!

Read the seed packets. Seed packs are usually full of great information that pertains to the species or variety of seed you’re planting. Things like how far apart to plant the seeds and whether the plants do well in full sun or partial shade should be on the seed packet.

Place your planting containers on a tray or in a shallow baking dish that will hold water. When it comes time to water your seedlings, gently pour lukewarm water into the tray or dish. Watering in this manner will not disturb the seeds as watering from the top often does.

Place seeds on the soil and cover with a light amount of your sterilized soil, no deeper than 2-3 times the width of an individual seed. Certain seeds, like the lettuces, do not germinate well with a soil covering. In those cases just press down on the seeds. In the garden we step on the lettuce seeds and they’re planted!

Cover the container with plastic wrap, a plastic bag or a piece of glass in order to retain moisture. Until the seeds actually germinate don’t put the containers in direct sunlight which could heat up the soil too fast and possibly dry it out.

To add a little warmth to the soil you can place the containers on a heating mat or other radiator.

Remove the plastic or glass coverings when the seeds germinate and place under florescent lights. Sunny windows are not sunny every day and those cloudy days can lead to some spindly growth. Place the lights about 3-4 inches above the seeds and raise the lights as the plants get taller. Lights need to be on about 16 hours every day, so use a lamp timer to make this a no-brainer.

Water seedlings from the bottom by adding water to your tray, but remove any standing water after about five minutes. Refrain from fertilizing seedlings until they grow at least two sets of true leaves.

Gardening and Seed Catalog Database Should Help Recycle Gardening Information

I’ve been collecting seed and flower catalog information over the last few days. The Internet has so much to offer that it’s pretty easy to be overwhelmed by the amount of information out there.

To make it a little easier to find the information about the offerings of the different gardening catalog companies, I’m creating a database. In the future all I’ll have to do is refer to information that I’ve already gathered to recall where I purchased a particular seed or plant. The seed catalog database will have information about the companies and the products they offer, as well as reviews of the online and print catalogs.

In the spirit of helping others I’ll make the database available to anyone stopping by – I’ll even let you download a pdf file of the database contents whenever it’s ready, that is.

So far I’ve requested a couple dozen print catalogs to be sent to me via snail mail. I know some of these will take 3-4 weeks to get to me due to the printing/mailing process, but I can wait. Here in central Pennsylvania the planting season doesn’t start for a few weeks yet.

Why would anyone who is green-minded, like myself, order anything in print that is available in a digital format? Even though I’m acting like a consumer by requesting that something be physically created and shipped to me, what I do with those items can help to offset the costs I’ve put on society, indeed consumer-driven society. If I can find a way to adhere to the three laws of recycling, reduce-reuse-recycle, I know I’ll feel better.

First, many of the seed and gardening catalogs stem from a long history of providing information to prospective gardeners. The shift to using the Internet for providing that information is happening, but at a slow rate. More companies have more catalog offerings on their websites now than at any other time, so that’s a good thing. A few have done away with print catalogs entirely – Bravo! The savings in printing and postage costs should help those companies survive and do well. Reducing costs and paper waste adheres to the first law of recycling, reduce.

Next year, I won’t be ordering those catalogs again because of the information I’m picking up now. Avoiding consumption should be emphasized more often, but we do live in a consumer-driven society and change is difficult. We can still try though!

Second, gardening catalogs are easily passed from one person to another and many of the ones I expect to receive will be shared in this way. Reuse is the second law of recycling.

Third, any catalogs that don’t pass muster will promptly be fed to the worms. Composting paper with food wastes is easy to do and will let us recycle those old catalogs that are no longer needed. Obeying the third law of recycling just makes ya feel good! Recycle.

Don’t have a worm bin or a place to compost your old papers? We’ll have to investigate what other options you might have for recycling your old catalogs in a future post.

Can anyone offer what they do to reduce-reuse-recycle with respect to all the catalogs they get in the mail? Leave a comment!