Seed Starting Guide

Direct Sow

Garden Jargon Glossary

  • Annuals: Plants that complete their life cycle in one year.
  • Biennials: Plants that complete their life cycle in two years.
  • Perennials: Plants that live 2+ years.
  • Direct Sow: To plant a seed in a garden bed outside.
  • Start: To plant a seed in sterile potting medium indoors.

Are you here just for dates? Cool, just download and print my planting guide for what to start when.

Prefer a visual guide? Check out our seed starting video.

Want to know two different methods for starting seeds indoors?  Ask two different gardeners.  And they will both be right.

For years, I have been reading articles, gardening books, and blogs. I’ve sifted, sorted, and experimented with this information and created a system that works really well…for me. I’m going to lay out my method, so you can begin to to sift and experiment on the path to find your own perfect seed starting method. 

Create a Seed Starting Plan

Plans: 2023, 2022, 2021

First, I list all the plants I’ll be starting from seed. Then I refer to my planting guide for starting dates and then begin to organize everything by month. Then I sort them further into lists of direct sow and starts. 

Do I have to wait?

I have a tendency to sow seeds a few weeks early. Since I know I’ll lose a few to rot and pests (or have to up-pot if starting indoors) I sow additional seeds around the recommended dates to be on the safe side. By June, I usually can’t tell which I started early and which I started on time. The seeds appear to have built in intelligence on what they should be doing when and how fast. So if you’re itching to get sowing—go for it!

Seed Age 

Seeds lose vigor with age, some faster than others.  According to the Sustainable Gardening Handbook here are some averages on how long seeds remain viable.

  • 1 year: sweet corn, onion, parsnip, leek
  • 2 years: okra, parsley, 
  • 3 years: asparagus, bean, carrot
  • 4 years: beet, mustard, pepper, pumpkin, tomato
  • 5 years: broccoli, Brussels sprouts, cabbage, cauliflower, celery, collard, cucumber, eggplant, kale, lettuce, spinach

Since I don’t take special care to maintain consistent cool temps and low humidity, I don’t keep seeds over two years. If there’s a question, I’ll germinate some seeds in a wet paper towel to get a feeling for their vigor. If they seem weak, or have a high failure rate, then I won’t waste my time with the batch. 

Starting Seeds Indoors

Gather Materials

Indoor Seed Starting
Top shelf relies on sun, the bottom shelf has a grow light. I rotate them daily.
  • South facing window and/or a grow light.
  • Seeds
  • Sterile Potting Soil (Some people get seed starting soil, I use cheap stuff that has served me well.)
  • Paper Pot Maker (I like this one, but any rigid, two inch cylinder will do.)
  • Paper: newsprint or seed catalog paper (not shiny)
  • Trays
  • Craft sticks
  • Sharpie
  • 4” plastic pots for up potting.
  • 4″ plantable pots for up-potting cucurbits.

Southern Window vs. Growing Light

Germinating seeds in our south facing window served me well for many years, but since adding a small grow light, I noticed increased vigor and sturdiness of the starts.

Seedling heating mat?  

I’ve done well without one, but many of my gardening friends swear by them. The Solanaceae, Cucurbit families as well as some herbs like cilantro and basil would appreciate the extra warmth.  


I bought this Paper Pot Maker from Amazon and have made hundreds of paper pots from seed catalog paper and still find it fun. The pots breathe well, wick water like champ, and you can plant the whole thing in your bed (or a larger pot) minimizing root disturbance.

Paper Pot Maker

The Process

(Watch our seed starting video!)

  1. Dump some potting soil in a bucket.
  2. Make the pots.
  3. Hold the pot over the bucket and gently fill with soil.
  4. Place in the tray.
  5. Repeat until they are all filled with soil and resting comfortably in the tray.
  6. Poke in your seeds.  (Basic rule of thumb, twice as deep as the seed’s diameter.) I usually add two seeds per pot. Very tiny seeds like chamomile should be sprinkled on top and sprayed with a misting water bottle. 
  7. Mark with a craft stick or write on the side of the pot.
  8. Label the tray with the date started. (And note in your plan.)
  9. Water the tray two-thirds of the way up with lukewarm water.
  10. Let the water wick up the pots and refill the tray if needed. The seeds need to be wet to initiate germination. Just as if they were outside in the rain. 
  11. Once the seeds sprout, they need to be moist but not soaking wet any longer.

Watering: Check on your seeds daily. Touch the tops of the paper; if it feels crispy, add lukewarm water to the tray.  

Light: Once the seeds sprout ensure they get the sunniest window (this might involve moving from window to window and shifting them around so they don’t shade each other.)  Or flip on your grow light. I follow the light cycle of the day.

Nutrients: Each seed contains enough food and nutrients for the plant to put out its first set of true leaves. (Seed leaves are the first to emerge, then true leaves.) Once the reserves are exhausted they must get nutrients from the soil and energy to make food from the sun. In general, my potting soil is not enriched. So at this point I begin to add a little liquid nutrition to their water. My favorite is an organic liquid called Buddha Grow by Roots Organic. Organics are better for us, the planet, and more forgiving to work with because organics take longer to break down, so there is less risk of nitrogen burn.

Up-Potting: Many of your babies are going to burst out of their paper pots before they are ready to go outside. I’m looking at you tomatoes and squash. Keep a supply of fresh potting soil and 4” plastic or plantable pots handy. I up-pot when the roots push through the paper and the sprouts looks sturdy. I add a little soil to the bottom of the new pot, pop in the paper pot and gently sprinkle soil around the edges to fill the new pot.  

For the cucurbit family (cucs, squash, melons) use plantable 4” (or larger) pots to minimize root disturbance. Everybody else is pretty happy in the standard 4” plastic pots until transplanting time. If you use recycled plastic tubs ensure you put a few rather large holes (1/2″ or so) in diameter for drainage.

At this point I swap the flimsy plastic trays for something sturdier, like cookie sheets. 

Tips: Check in daily. Rotate them around to get even sun exposure for everybody. Check the moisture level and water with room temperature water. Remember to add nutrients to their water once a week or so.  

Direct Sowing

Direct sowing requires a little more advanced planning than indoor sowing. The first step is to decide when you want to start seeds, then begin to prep your beds a few weeks before. The goals of bed prepping are to reduce the overburden of slugs and decomposer insects, give cover crops time to breakdown and release nutrients, and to expose soil to the sun for warming and drying.

Here in Willamette Valley, Zone 8b, I begin this process late February or early March.

Soil Temperature: Most cool tolerant crops need at least 40 degrees Fahrenheit to germinate. Warm season crops like 50 + degrees. Some need 60!

Moisture: Soil should be moist, but not saturated. Raised beds have the early season advantage of better drainage, but also dry out quicker in the summer.

Soil depth: An easy rule is to plant seeds twice as deep as the seed’s diameter.

Spacing: Space seeds as advised in my planting guide. For peas, beans, and beets, use one seed per hole. For other crops sow two or three seeds per hole. Then thin to one plant per spot later.

Fertilizer: Seedlings (except carrots and beets) will need nitrogen once the first set of true leaves appear. It works well to fertilize and sow the seeds at the same time. I use an organic feather meal (NPK 16 – 0 – 0) from Down to Earth Organics which will require a time to break down and become available. My soil has plenty (read overburden) of the other nutrients, so I this is perfect for me. (Soil Testing) Carrots and beets are considered light feeders and form a better root with less available nitrogen.

Beware of a Late Frost: If the forecast predicts a late frost, or you get that tingle in your bad knee, put a cloche, plastic or fabric sheet over your seedlings at night.

Beware of an Atypical Dry Spell: If the forecast calls for a few days of dry and windy weather, be sure to water in the morning.


Keep up on your slug IPM! Slugs are the biggest threat to germinating seeds in my region. (Willamette Valley, OR) I don’t try to eradicate them, and I also accept that I will have losses, but I also want to ensure a harvest for my family.

Steps for both Indoor and Outdoor Sown Seeds

Thinning: As my friend Maggie Stuckey says, “It is hard to make yourself do this; it feels wasteful and murderous. Do it anyway.” (Gardening from the Ground Up, Maggie Stuckey) In pots, select the one that is the most vigorous and clip the others. In your beds, clip all but one using the space requirements as a guide. Tip for outdoor sown seedlings: do this in rounds. I lose enough starts to pests that I will do a light thinning first, and as they grow, go back once or twice more to give the allotted space. I allow pests to do some of the thinning for me.

Trouble Shooting

Failure to Sprout 

  1. For indoor starts or summer sowing: the soil could be too dry. This is the most common issue because people are generally worried about overwatering their seeds. I’ve re-sowed some pots only to have the original seeds germinate when they finally got the water they needed. Oops! A clear plastic cover over your unsprouted seeds will keep them warmer and keep the air humid.
  2. Some seeds, like perennial herbs such as lavender, peppermint, and onions take a long time to germinate.  Double check your seed packet.
  3. They needed cold stratification, but didn’t get it. (Many meadow flowers need this.)
  4. Is it too cold? This is generally not an issue for indoors, but if you’re growing in a basement or greenhouse, check the temperature. Many cool tolerant seeds need a soil temperature of 40+ to germinate. Warm season crops might need 60+ degrees.
  5. The seeds could be duds. (Seeds lose vigor with age as well as temperature and humidity fluctuations.)

Yellow Leaves Mean

The plant is lacking in nitrogen and needs to be fertilized. I go for a liquid fertilizer, to give a more immediate boost, then side dress with a little organic feather meal.

Long Weak Stems

Leggy seedlings are searching for light. Add light and a slight breeze, if possible, and the plant should be able to strengthen its main stem.

Wilted Plants

If the soil is dry, (crispy at the top of the paper pots) they need water. If everything is already wet and your plant is droopy, then they are drowning due to over watering or heavy rain. Unfortunately, the symptoms look the similar.

More Resource for Seed Starting

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: