With a little help, potted plants can benefit from food webs in soil

It is time to answer some emails.

First, I was amazed to have two people ask me if it was OK to start using their outdoor greenhouses. You bet it is! The idea of a backyard greenhouse in Alaska is to extend the season, remember?

In fact, if you have not fired up the fan in your outdoor greenhouse, cleaned things up and started to use it, then you need to ask yourself why you have one — and get to it.

I don't usually mention it, but those greenhouse fans and any associated motorized venting should get the same treatment your lawn mower gets this time of year: a thorough inspection to ensure things are in top shape and it will get you through the season.

There is nothing worse than coming home on a sunny day and finding your fan has failed and your tomatoes got stewed, literally.

Ideal temperatures for growing plants in these greenhouses are in the mid-70s, so adjust your thermostat accordingly. Don't be fooled into thinking 90 degrees is better.

Next, do I buy new soil for use in my containers every year? This is a great question, one I get from indoor cannabis growers all the time as well. My answer is that I do not buy new soil every year and I don't think you need to either — provided you are an organic soil food webbie.

The general concept is the plant grew in that soil and put out the exudates to attract the right microbes. They are still in there and ready to feed the plant.

My advice is to start out with the best stuff you can find: great compost, preferably your own. Mix in a bit of sand and perlite for drainage. Test it for nutrients (I know, no one does, but you should), and make sure it will grow plants.

When you plant for the first time, add a layer of microbe food/fertilizer about one-eighth of an inch deep as you fill the pot. Add this layer about one-fourth of the way up the pot so roots will grow into it. Use organic mulch on the soil surface in all your containers.

If possible, leave the soil undisturbed except for where you are putting the plant or seeds in. The old roots not only provide organics to the soil, they return nutrients taken from it and are used as pathways for new roots.

Use soluble, organic fertilizer and a half-inch or so of compost on the surface. Both will go a long way to feeding those all important microbes in the container's soil.

When you do want to use new soil, dump the old stuff in the compost pile and mix it in. The soil-food web in your pile will remineralize it for reuse.

I can't believe it, but a few folks are already wondering if it's too early to harden off! Hardening off, for those who don't know, is acclimating indoor plants to growing outdoors.

There used to be an elaborate, weeklong protocol for doing this involving moving plants from shaded areas after a few days to dappled shade and then full sun. Now, most of us simply put the plants in the shade for a week.

Anyhow, apparently there are folks going on vacations or perhaps they are simply impatient or willing to take the risk of a frost.

Usually we don't start to harden off until mid-May in Southcentral, when the birch leaves reach the size of squirrel ears, as the saying goes. The explanation behind this rule of thumb is that Mother Nature isn't freezing those new leaves, so it's relatively safe to assume hard frosts are behind us.

Right now you can harden off peas and sweet peas, and even plant them if the soil has thawed. You can risk other things, too — if you're willing to pull them inside should temperatures drop below freezing.

Finally, the lawn. It does not need thatching in the spring. It does not need feeding either. And it surely doesn't need weed-and-feed products that require much higher temperatures to be efficient, including Roundup products (please, no trolling; the stuff is just not good).

Just water your grass. That is all. Don't be a sucker for all the lawn ads, pretty labels and the like. I'll get you there. Just keep asking the questions.

Jeff’s Alaska Garden Calendar

Nurseries are open: Visit many and often during the week. Look for sales.

Vegetables to start from seed: Broccoli, cauliflower, kale, cabbage, head lettuce, pepper.

Flowers to start from seed: Achimenes (tuber), brachyscome (15C), dianthus (5), stock (10L), larkspur (20C). (The numbers show the number of days to germinate the seeds. C means grow cool, and L means the seeds need light.)

Herbs to start from seed: Sorrel

Wildflower classes: May 11 through June 1, Dr. Marilyn Barker and Ginger Hudson will teach classes in field botany at the Alaska Botanical Garden. Participants will meet four consecutive Thursdays. Morning and evening sessions are available. For more information, or to register, visit alaskabg.org/local-wildflower-class-2/ or call 907-770-3692.