Beginners Guide: When to Start Seeds for a Great Garden

When should I start my seeds? This is a question I ask myself every year, and an answer I forget every year. I think one of the reasons I forget is because the winter blues hit hard, and by the time the end of January comes around all I want to do is get my hands in some dirt.

That being said, if you’re a beginner gardener, understanding when to start your seeds is one of the most important lessons you can learn.

Starting Questions

Before I can tell you when to start your seeds, there are a few prerequisite questions you’ll need to answer.

Do you want to start from seed?

I think starting plants from seeds is incredibly rewarding, but it is not for everyone.

I recommend starting plants from seeds to folks that:

Have patience
Like watching things grow
Want to learn the growing process
Plan to have a very large garden
Want unique varieties of flowers/vegetables that are harder to find in nurseries
Have a strict budget

I do not recommend starting plants from seeds to folks that:

Do not want to wait weeks to months for their first harvest after planting
Plan to have only one of each plant on a patio or other small space

The reason I don’t recommend starting plants from seed if you are planning to plant only one of each type of a fruit, vegetable or flower on a patio or other small space is that I don’t think the investment is worth it. Financially, most beginner gardeners don’t know that seeds are most viable in the first one to two years after harvesting. That means you’ll still need to buy new seeds each year. For the same price of buying a pack of seeds, you can usually buy a started vegetable plant from your local mom and pop nursery. That started plant will be ready to plant and you will not need to invest time and effort in germination, proper lighting, hardening off or up-potting the seedling.

What type of seed starting setup can you afford?

One of the most common motivators for gardeners to grow their plants from seed is funding. For the same price of one started tomato plant you can buy a seed packet with over 20 seeds. That being said, if you aren’t careful, a seed starting setup can go from $0 to hundreds of dollars very quickly. You do not need an expensive setup to start seeds.

The most common ways to start seeds are: winter sowing, a sunny window, a green house, an indoor seed starting station and direct sowing. Each of these methods can vary in price depending on what you already have at home and how fancy you want your setup to be. In general, if you’re starting from scratch, the winter sowing and direct sowing methods are the least expensive and the indoor seed starting station is the most expensive. The greenhouse method completely depends on whether you already have a greenhouse or not.

The main factors that increase cost are:

Planting Containers: Are you willing to reuse “trash” or do you want an official seed starting tray? Are you planning to buy a disposable seed starting tray or do you want one that is more heavy-duty that you can use from year to year?
Lighting: Obviously the sun is free, but if you’re planning to add your own light then you need to decide if you want a plant light or if you’re open to using a shop light.
Soil: Are you planting in containers or directly in the ground? Do you want to use seed starting mix?

Winter Sowing is a great method for perennials.

What are your space limitations?

An indoor seed starting station is the most common way to grow plants from seed. The reason for this is that you can start your seeds earlier and that means you can harvest your crops earlier. This takes space! The earlier you plan to start seeds indoors the more room you will need for the seedlings to grow before temperatures are warm enough to move them outside.

If you don’t have a ton of space indoors for baby plants you can very easily plant the seeds later so that they don’t grow as large indoors, use the winter sowing method or direct sow your seeds in their permanent growing place.

When is your first and last frost date?

On every seed packet and online forum you will see a line that says “Plant *x number* of weeks before your last frost.” This number usually designates when to start your plants via an indoor seed starting station. The date of your first frost date comes into play when thinking about harvest time. For example, if you want to plant a variety of tomatoes in which the time to maturity is 90 days, you’ll want to make sure you plant your seeds at least 3 months before your first frost or you probably won’t be able to harvest any mature fruit.

I like to find my average first and last frost date by utilizing the Old Farmers Almanac Planting Guide.

When does your soil warm up?

If you’re planning to direct sow your seeds, you’ll need your soil to not only be workable but also be warm enough to promote germination. This temperature ranges depending on what you’re trying to plant, but normally you wait for soil temps to hit the 40’s to 50’s for cold weather crops.

GreenCast has an awesome interactive soil temperature map. You can enter your zip code, then click on the date range and click on “Previous Year.” I recommend looking at the 10 year average to plan when to direct sow your seeds.

Perennial or annual?

Some plants, usually temperate perennials, require a time of “cold stratification” before they can germinate. You can mimic this process in your refrigerator, but you can also accomplish this process via winter sowing in the dead of winter or direct sowing in the fall.

When to Start Seeds

Now that you’ve answered those questions it is time to figure out when exactly to start your seeds. This is when I recommend starting seeds for each of the aforementioned growing methods:

Winter Sowing:

Winter sowing is a cheap set-it and forget-it method of seed starting. White Earth Tribal & Community College has a great resource to teach you how to use this method and you can find it here.

If you are trying to plant a seed that requires a cold stratification period, I recommend starting your seeds in the dead of winter. You want these seeds to spend a good three-plus months in the cold without any unseasonably warm thawing out periods. If you plant them too early and then it warms up for a couple weeks you may have some of your seeds germinate too early and then die in the next cold spell. In Maryland, I usually plant my flowers and hardy perennials in January. Depending on where you live, you could plant your winter sowing seeds as early as November.

If you are trying to plant a seed that is for a more tropical or warm season plant, I recommend waiting to winter sow your seeds until the super cold nights are behind you. Below freezing temperatures may kill those seeds. I usually plant my winter-sown pepper seeds and tomato seeds at the end of March or beginning of April in Maryland.

Sunny Window:

The sunny window method can be another cheap set-it and forget-it method of seed starting but you have to wait until a bit later in the season.

If you are looking to start your seeds in a sunny window, then you will want to wait to start your seeds until your house is warm enough and until your days are long enough. If you keep your house at 63 degrees Fahrenheit in the winter like I keep mine, many of your seeds will not germinate quickly just because it is just not warm enough for them yet. In terms of light, many seedlings need light for over 12 hours a day in order to develop properly. I don’t recommend starting your seeds in a sunny window until after the spring equinox (March 20th) and I’ve had the best success waiting until May or June.

Indoor Seed Starting Station

The indoor seed starting station method is the most common method to start seeds and often the most straightforward for beginners, but it is also the most likely to be expensive. You will need a grow light and optional add-ons include heat mats, humidity domes and seed-starting trays. When starting seeds indoors at a seed starting station you will want to base your seed starting on your last frost date. The University of Minnesota Extension has a great page about how to set up your indoor seed starting station here.

If the seed packet says start seeds 6-8 weeks before your last frost date then the earliest you should start your seeds is 8 weeks before your last frost. This does not mean you have to plant your seeds that early!

An example, it is recommended that you plant most peppers 8-10 weeks before your average last frost. Normally 10 weeks before my average last frost date is the end of January, but I have planted pepper seeds in the middle of July before and still had multiple harvests before the first frost in the fall.

Greenhouse and Direct Sowing

I’m clumping using the green house and direct sowing methods together because both of these methods depend almost exclusively on temperature. If you have a greenhouse already both of these methods can be free.

Plant your seeds in the garden beds of your greenhouse or directly in your outdoor garden beds when the soil temperatures reach the minimum temperature for seeds to properly germinate. A great resource for that is this PDF by the University of California.

You can also use the greenhouse or direct sowing methods for containers. The biggest difference between container gardening and in-ground gardening is that the soil in containers will warm up more quickly, but also cool down more quickly. That means you should generally base your planting times on the ambient temperature rather than in ground soil temperature. The growing season for container gardening is shorter than that of indoor gardening unless you plan to bring your containers inside.

If planting in a greenhouse, the soil inside the greenhouse will warm up sooner than the soil outside and stay warmer longer in the fall. That being said, you may be limited by your summer temperatures. It is possible to cook your seedlings.

In Conclusion

In conclusion, when to start your seeds depends heavily on what method you are using to grow your seeds and what kinds of seeds you are planning to grow. Don’t be afraid to try a few different methods and test out what works best for you! And don’t limit yourself to the seed starting packet. You can always buy starts from your local nursery as a back-up plan.

No matter which method you choose, I highly recommend keeping notes so that you can remember what works for you and what doesn’t. Personally, I really like keeping a detailed journal for my gardening journey. I use a simple bullet journal, but I’ve seen some folks create awesome garden scrapbooks, and there are a variety of really detailed ones online. I published a minimalist garden journal online that you can purchase via Amazon if you’re interested.

Last note, you may hear folks refer to planting your seeds via the lunar calendar or planting by the moon. This method still involves taking temperatures into account, but puts a specific focus on the phases of the moon. The theory is that you should plant seeds that need to focus on growing down during the waning phases of the moon and plant seeds that need to focus on growing up during the waxing phases of the moon. The phase of the moon affects the field of gravity and will “pull” your roots down or your shoots up. Following this method you’d want to plant your perennials, biennials, bulbs and root vegetables during the moon’s waning phase and your annual flowers and vegetables (like tomatoes) during the waxing phases of the moon.

I hope this information has been helpful and good luck with your gardening journey!

Additional Resources

Online Resources:

I always recommend taking advantage of the knowledge offered by your local university extension office. These are some of my favorite online guides to seed starting:

University of Georgia Extension – Starting Plants from Seed for the Home Gardener
University of Maryland Extension – Starting Seeds Indoors
University of Maryland Extension and Master Gardener – All the Dirt on Winter Sowing
University of New Hampshire – Starting Plants From Seed [fact sheet]

Books I love:

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