Seed anatomy, food stores, respiration, breaking dormancy

I like to start at the beginning, so that everyone has the same foundational knowledge of what a seed is, and what is required for a seed to grow. A seed is a plant in a state of dormancy- it’s still alive, it’s breathing and using up it’s food stores, just very, very slowly. Every Seed has three parts: the embryo, the cotyledons, and the seed coat. The embryo is fairly obviously what will become the main plant. The Cotyledons, or cotyledon if it’s a monocot like corn, are what is often called the seed leaves. These serve are food stores while the seed is dormant and in the first stages of growth, and then they are the first leaves to photosynthesize after the seed has sprouted. The seed coat protects the seed, and helps keep it dormant until the time is right.  

To begin germinating, to start actively growing, seeds really only need two things: water and sufficient warmth. Until a seed gets enough water, it will be slowly using up it’s food stores- until it runs out. This is why it’s best to keep seeds in a cool, dry place. The cooler the seed is kept, the longer it’s food stores will last. The more food stores a seed has, the more vigorous it will be when it does germinate. Note, especially if you intend to start some flowers and perennials, that the seed coat sometimes is so protective that you have to damage it somehow to allow water to reach the embryo- most commonly grown vegetables and flowers don’t require this, and those that do will come with instructions.

To make a successful, thriving plant, we need to provide seeds with more: soil for nutrients and to anchor the growing plant, light, warmth, and water.

Basics: soil, light, warmth, water, and containers.

Soil: To get seeds started, they don’t need rich soil- in fact, lots of people start seeds in inert media, like sand, vermiculite, and perlite, that have no nutrients, and then transplant the tiny seedlings into soil later. Do not plant in straight manure or unfinished compost- too much nitrogen can burn them. I typically use garden soil, or garden soil mixed will finished compost and used coffee grounds. If you are using soil from the garden, you may want to consider sterilizing it so that weed seeds don’t germinate and compete with your own seeds. You can do this by baking it in the oven, or by pouring boiling water over it and stirring. You can of course buy seed starting material, which works very well.

How to sterilize garden soil for seed starting:

Preheat oven to 180*. Put soil in a pan, about 3 inches deep. Measure temperature with a thermometer, and once soil temperature reaches 180*, bake for an additional 30 minutes.

Light: You want as much light as you can get. A south facing window works well, if you get the seedlings as close as possible to the window for the most direct light (one caution here is that the area near windows can get too cold for some plants in the depths of winter- I’ve had cold damage on basil in the window). You can also buy grow lamps- I use t-5s, my mom uses shop lights- get cool white bulbs, or a mix of cool white and warm. Keep it simple, and don’t go overboard. Buy used- old fish tank lights work really well. If you buy new, look for shop lights, not seed starting lights or plant lights- shop lights are way cheaper, and will work well for seed starting purposes.

Warmth: Seed packets will tell you the temperature ranges that the seeds germinate and grow the best in. Generally, if you’re indoors, it’s warm enough. For starting heat lovers, like tomatoes, a favorite spot is the top of the refrigerator. Anywhere that’s a little warmer will work well, but make sure they have ample light as soon as you see any part of any seed break the surface of the soil.

Once they are sprouted, I’d recommend moving them somewhere a little cooler, if possible, unless you have the strongest of lights. The warmer the seeds are, the faster they will try to go, and if they don’t have enough light, they’ll get leggy. That means they’ll be floppy, and more vulnerable to damage.

Water: Water enough, but not too much. One of the most common killers of any indoor plant is over-watering. You want the soil to look moist, but not have standing water, and not be soggy. Too wet soil will increase your chance of losing seedlings to damping off and other fungal diseases. Don’t let them dry out. I recommend watering from the bottom- put your container in a tray, and fill that with water. The soil will absorb what it needs, and I dump any excess water after an hour or so.

Containers: You can use basically anything that will allow water to drain and that you can easily remove the seedlings from when it’s time to transplant. Some people use seedling trays; others use coffee cups, yogurt containers, egg cartons, etc. I really like to use newspaper pots, especially for bigger seedlings that don’t like being transplanted- squash, pumpkins, and corn for example. I use newspaper pots because they are free, you can make them in a range of sizes, and when it’s time to transplant, the newspaper is easily torn away if it hasn’t already started decomposing. You can also get one of those soil block makers and use them.


When you start your seeds depends on the type of seed, how much cold they can handle, how risk averse you are, how willing you are to baby them, and when you’re last frost is. Unfortunately, our frost date can jump around from year to year, and varies a lot depending on your micro climate. If you are close to an urban area, or near a body of water, freezing nights will stop sooner and you’ll be able to plant out earlier in the year. If you are higher up in the hills and further away from urban areas, you’ll have a shorter growing season. Unfortunately, different sources list different average last frost dates for Olympia, so it’s a matter of how risky you are willing to be, and how far you’ll go to ensure your plants survive. I’ve seen average last frost dates ranging from Mid-April to nearly the end of May. I personally assume a last frost date of about May 6th.

If you have or build a lean-to, cloche, or other insulating structure, you have more flexibility. You want to keep your plants growing quickly and strongly, and if you run out of space in your growing area, that’s a problem. I don’t start tomatoes earlier than February, and I don’t start squashes until mid-April.

Minimizing transplant shock

  1. Plant out before they get root bound!!!!
  2. Harden off! Don’t sunburn or expose plants to suddenly cooler temperatures- work up to it. Start by putting seedlings outside in a sheltered area for a couple hours a day, gradually working up to over night.
  3. Use newspaper pots/other biodegradable pots.
  4. Firm the soil, water deeply, and protect.

Seed companies:

I like to go with companies that are local, or are in a similar climate. That means they are breeding plants to be successful in our area- if I’m buying from a seed company in say, Iowa, the plants were selected for a very different climate- one with long, hot summers. A lot of varieties need more heat than we get to thrive without a lot of extra work. If I’m trying to grow warm season crops, then I need to look for somewhere that has as mild a summer as we do. Conversely, I also like to plant for overwintering crops, and our winters are milder and moister than many areas, so I need to select varieties that are resistant to rotting or mildewing in the field.

My favorites:

Osborne: Aimed towards market gardeners and small farmers. Fewer of the heirloom and open pollinated seeds; more hybrids aimed to be successful for people selling at a farmers market.

Uprising Seeds: 100% open pollenated and Pacific Northwest grown. Lots of niche and unique varieties.

West Coast Seeds: Based in BC, so these are selected for an even cooler climate than ours! Mostly open pollinated and hybrids; all seed is untreated.

Adaptive Seeds: Devoted to genetic diversity- seeks out neat varieties from around the world. Heirlooms and open pollinated. Lots of niche and unique varieties. 

Territorial: Standby of home gardeners, good reputation, grown in Oregon. Good variety of varieties.

Nichol’s Garden Nursery:  Another Oregon-based companies, like territorial, but some more of the interesting, niche varieties.

When picking warm-weather varieties to try (tomatoes, pumpkins, squash, corn, etc), look for plants that reach maturity in 70 or fewer days (except squash/pumpkins, they tolerate a little more cool weather if you pick carefully), and look for these key phrases:

  • Thrives in cool weather
  • Ripens where others won’t
  • Among the first to ripen
  • Earliest to mature
  • Cool weather

Recommended squash varieties: “Oregon Homestead Sweet Meat”, “Candystick Delicata”, and “Small Sugar” pie pumpkin.

Useful links:

USDA Hardiness Zone: Plug in your zip code, find out your zone!

Thurston County Master Gardeners: Keep reading, there is lots of info!

WSU Gardening: So much incredibly useful information, you could be reading for days.

Gardening forums:

r/gardening: the most active, lots of helpful people and links.

Dave’s garden

Gardenweb: they used to have a much better setup, but still…

Washington/Pacific Northwest specific gardening guides:

Mother Earth News Pacific Northwest gardening guide

Westside Gardener (that’s the west side of the Cascade range).

NW Edible’s guide:useful blog with gardening calendar, from the Seattle Area

Rodale’s Organic Life Monthly Garden Calendar for Pacific Northwest United States

Seattle Tilth: they publish a lovely guide, and their website is kind of helpful too.

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