Starting Seeds: Best Practices

Starting Seeds: Best Practices

Spring may be just a glimmer on the horizon, but we're already brimming with excitement as we think of all the things we're planning to grow in our gardens this year. And the good news is: Even though it's still too cold to plant most crops outdoors, we can get a head start on the growing season inside! Longtime gardeners know that when the crocuses start to poke their heads up in February, it's time to begin thinking about starting a few seeds indoors. Growing out seedlings inside allows you to transplant them into the garden once the threat of frost has passed and start the growing season with plants that are already weeks closer to harvest. Keep reading to see get started with seed starting in the Pacific Northwest. (And don't forget: If you encounter any vocabulary that stumps you along the way, try taking a look at our handy Edible Gardening Glossary.)

Getting Started

When starting seeds, most of the information you need is located right at your fingertips — namely, on the back of the packet your seeds came in. A lot of vital information can be found on seed packets, from the number of days to harvest to planting depth, spacing, and timing. Most planting dates are given in relation to the first or last frost date of the year, which will vary based upon your location. (You can check the average frost dates for your zip code here.) Keep in mind that it's better to air on the side of caution and start your plants a bit on the later side, especially if you're just starting out. You don't want to start your plants too early, or the conditions outside may still be too cold to transplant them out when they come to size.

Gather Your Supplies

Once you know when to sow your seeds indoors, you can figure out a plan and begin gathering materials. Below, you will find a recommended list of basics to get you started:

  • Seed-starter soil
  • Plant lights or regular lights
  • Heated seed mat(s)
  • Seed trays
  • Humidity domes
  • Soil blockers or containers with drainage holes
  • Waterproof pen
  • Labels

Find a Good Window

Light is incredibly important to seed growth! Here in Portland, where skies are gray for most of the winter, you will likely need to provide supplemental light for your seedlings to ensure that they grow strong, healthy stems. But even so, there’s nothing like the real thing. If you can, find a spot for your seed-starting near a bright window. Keep in mind that the direction the window faces makes a big difference. Window direction in order of desirability is: south, east, west, north.

  • Even though a south-facing window will provide the best light, keep an eye on seedlings you're growing in this exposure. The sun's rays may be too sensitive for some seedlings at certain times of day. If this seems to be the case, try moving them back a few feet or adding a sheer curtain to solve the problem.
  • Keep an eye on west-facing windows for the same reason, although supplemental light may still be needed.
  • Morning sun in an east-facing window should work well, but supplemental light will probably be needed.
  • With north-facing windows, you will certainly need supplemental light, but the seedlings will still appreciate the addition of indirect sunlight.

If using grow lights, it’s best to place them just a few inches above your seedlings. Just watch to make sure they aren’t giving off too much heat. Regular light bulbs will help, but plant lights are even better.

Once your plants germinate, if you notice that seedlings leaning, it's a good idea to rotate the tray so that they grow evenly.

Planting & Soil

Take a look at the back of your seed packet to see how deep they would like to be planted. Generally speaking, the bigger the seed the deeper you plant it. Most seeds need darkness to germinate, but others need light and are just left on the surface of the soil. Also pay attention to how much space they require from other seeds. Plants that are too close to each other will stunt each others growth. Make sure to find out what's best for your particular seeds.

When starting seeds for your vegetable garden indoors, it's best to start with seed-starting soil mix for one simple reason: It is sterile. In other words, it's guaranteed to be free from soil-borne fungus, bacteria, insects, and weed seeds, giving your seedlings the very best chance at a healthy start. Additionally, these mixes have excellent drainage, which helps to prevent your seedlings from becoming over-saturated.

One mistake many beginners make is planting seeds in too dry of soil, then adding water, expecting that it will uniformly disperse throughout the growing medium. Sadly, it doesn’t work that way. Instead, the water will pool on the surface and run down the side of the container, never reaching the newly-planted seed — or worse, causing them to float away! That's why it's a good idea to start by pre-moistening the soil. To do this, put the soil you are going to use (or part of it) in a container with extra room for mixing. Don’t add too much water at once: gently sprinkle the surface of the soil with water, mix it in, then repeat the process until the soil is uniformly moist. You want it to be moist, but not wet. Roots need a combination of moisture and air to thrive.

Whether you're planting into containers or seed-starting trays, you're now ready to fill them with your pre-moistened soil and lightly tamp it into place. (Just be sure whatever you're growing your seeds in has drainage holes!)

After you have finished planting your seeds at the correct depth and spacing, be sure to label your planted seeds. Many seedlings and young plants look very similar to each other, and you will thank yourself later if you take the time to make clear, waterproof labels up-front. It’s also a great idea to draw a picture in your gardening journal with the plant names included as a backup in case a tag is lost.

Water & Humidity

Seeds need to be kept moist in order to germinate. One way to greatly increase your chances of success is to cover your seeds with a humidity dome until they’ve sprouted. You do want to ensure there is some air flow, though! Without air circulation, seedlings can suffer from fungus and mold issues — even if you're using sterile potting mix.

When it comes to watering, watering from the bottom is usually a better idea than watering from the top. Seed starting trays makes this easy — simply add water to the tray underneath your plants, rather than adding it to the top of the soil! If you water from the bottom, the soil will act as a sponge, lifting the water to the seeds. This encourages roots to grow downward. Watering from the top can cause soil compaction and lead to plants developing roots that are weak and shallow. It can also cause over saturation of the growing medium around the seed or seedling, which can cause issues with growth.


Depending on what you are growing, some seeds require a specific minimum soil temperature to germinate, which can generally be found on the back of the seed packet if this applies. This is a brilliant adaptation to give the resulting plant the best chance of success when it is growing without our help. Even though they don’t all require it, most edible plant seeds will appreciate it and will be easier to start when warm. If seeds are sitting in a warm window, they may be warm enough, but a seed-heating mat placed under your tray of soil is a seed starter's best friend.

Potting Up & Planting Out

Once your seedlings have germinated and start to look like miniature versions of the adult plant, you will need to make plans for what to do with them. If your seedlings start to outgrow their accommodations before the conditions outside are suitable for transplanting them out into the garden, you can give them more space to grow by pitting them up to a larger container. (A four-inch pot is usually sufficient.) Otherwise, they can go outside — but not without a bit of acclimating.

When starting seeds indoors, it’s important to “harden off” the young plants first. They cannot go straight from growing indoors into the ground outside. When the time is appropriate (read your seed packets), you can place your plants outside for increasing periods of time. This should take place over the course of about two weeks. The first day they should be outside for about an hour, and the last day they should be outside for the majority of the day. This allows the plant to adjust to, wind, varying weather, and direct sunlight. Then, you're well on your way to the veggie garden of your dreams!

With a little planning and effort, you can successfully start seeds to get a head start on the growing season. We have a fantastic selection of veggie, herb, and flower seeds in stock at the Farm year-round, but February is generally when we have the best selection. If you have any questions about starting seeds or picking the right varieties to grow in your garden, our Kitchen Garden team is always happy to assist you.