To better understand the plants you will grow, learn about the process that leads to effective germination

I am excited about starting seeds as it is now time to get things growing indoors so you have something to plant outside in mid- to late-May. Remember my updated motto: You don’t get bragging rights if you didn’t start the plant from seed yourself.

Gardeners used to take seeds and try to sterilize them before planting in a sterile medium in order to prevent damp-off. Now that we understand the role of microbes and the soil food web — thank you, Dr. Elaine Ingham — we have come to appreciate that you want these critters to help you germinate and grow seeds into plants. I have to wonder how plants even grew with everything sterile?

There are two obvious answers. The first is the sterility didn’t last very long and microbes got to do their thing, albeit late in some instances. The second, more plausible explanation, is that things were not as sterile as we thought.

It doesn’t matter if you consider this: We now know that seeds that have been grown for hundreds of years contain the same bacteria all along the spectrum from ancient times to today. These microbes help the seed germinate and then prime the soil to ensure it has the right populations. They have evolved to work with that type of plant. In other words, the microbes that support your heirloom tomato may not be the same ones that are helping your carrots. Fortunately, if we just let the plant do its thing without the use of chemicals, the plant is in control.

[New: Teaming With Microbes podcast: Gardening with science and the soil food web]

Bacteria, in particular, get trapped in a seed when flowers form seeds. They are endophytic, meaning living inside the plant. Consider the trust that must have evolved for the plant to allow a bacterium to live, multiply and thrive inside it and to be passed on to help the next generation. You have to believe those microbes are needed by the plant.

Going back to our sterile grow, we now know that special bacteria invade roots through a newly discovered process called rhizophagy, which you should learn about in my latest book “Teaming with Bacteria,” and actually are the cause of root hairs. No bacteria, no root hairs! Who knew? The initial bacteria must come from the soil or the seed. Hmmm.


And then consider what we know about plants producing exudates to attract their food. Makes us understand a bit more the importance of sustaining the germinated seed and not interfering with it until it can start photosynthesis necessary for the production of those exudates! That little tiny seed holds enough food and bacteria to grow leaves. Consider some of those tiny seeds, smaller than a period on this page, that develop into three- or four-foot plants!

What does this mean for you as a gardener? There are some 9,000-10,000 different kinds of bacteria in an average seed with a population of about two billion per seed. It should be obvious that you shouldn’t fool around with your seeds using hydrogen peroxide and the like. Using chemical fertilizers is obviously a no-no because they alter the microbiome. And, adding organics — kelp is great — and microbes to your soil will make the pool that can be utilized by the plant much greater.

Rolling seeds in mycorrhizal fungi or rhizobia in the case of legumes, will add to the microbiome in the immediate vicinity of a plant’s roots. Adding compost and living soil products will increase the pool of available microbes that can help a plant.

The role of seed-borne microbes should also affect how you store seeds. The old advice was to keep them in an airtight container. That is fine for a short time, but seed bacteria need to breathe to survive. Don’t store leftover seeds in an airtight container.

Finally, and this should be paramount, there is the wonderment that should come with the knowledge that seeds contain everything they need to carry forth a new generation, including the microbes which will feed them as they get off to a start and which will populate the soil in order for them to thrive. That plants form such symbiotic relationships with microbes is amazing.

Jeff’s Alaska Gardening Calendar

The “Teaming With Microbes” podcast: Jonathan White, the caffeinated gardener from Steamdot Coffee, will be prying information on organic gardening from me in a brand-new podcast that starts this week. Join us below or wherever you listen to podcasts.

Alaska Botanical Garden: On April 15, join debut Alaska author John Messick for an outdoors literary jaunt at the Alaska Botanical Garden, occasioned by the launch of his gorgeous memoir-in-essays, “Compass Lines: Journeys Toward Home.”

[Book review: In ‘Compass Lines,’ a restless young man finds his way to home in Alaska]

Alaska Master Gardeners Annual Conference: Party with Garden Friends on Friday, April 7, 5:30-7:30 p.m. at The Nave. Herbal Syrups demo, auction, appetizers ($50). Conference on Saturday, April 8, 8:30 a.m.-5 p.m. at UAA with 10 speakers and lunch ($120).

2023 Alaska Pioneer Fruit Growers Grafting Workshop: April 15 at Begich Middle School. The public is welcome to attend from 1-2:30 p.m. for grafting instructions. There will be numerous scions from many different apple varieties from which to choose!

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

Flowers to start from seed: Achimenes (tuber), brachyscome (15C), dianthus (5), Stock (need light), Lockspar (20C).

Herbs to start from seed: Sorrel

Nurseries: They are open! Early birds get the worms.

Yard work: Last call! It is time to pick up after rover. Wait any longer and you will be sorry. Frozen is better.

Mycorrhizal fungi: Use it on all seeds and transplants except for those in the Cole family. Rhizobia is a fungi that fixes nitrogen with legumes.

Jeff Lowenfels

Jeff Lowenfels has written a weekly gardening column for the ADN for more than 45 years. His columns won the 2022 gold medal at the Garden Communicators International conference. He is the author of a series of books on organic gardening available at Amazon and elsewhere. He co-hosts the "Teaming With Microbes" podcast.