How To Plan For Seed Starting Indoors (2024)

February 02, 2023 3 Comments

Starting seeds indoors is a fun and exciting way to bring the garden to life! Whether you are a seasoned gardener or a newcomer to the world of indoor seed starting, there are a few key things to consider to ensure success. With the right planning, you'll be well on your way to growing healthy, strong seedlings that will be ready to transplant into the garden in no time.

In this blog post, we will cover the important details to review on a seed packet, how to determine when to start seeds, how many seeds to start, pot or tray sizes, and how to make a schedule. So, grab your notebook and let's get started together!

The first step in planning your seed starting journey is to write down what you want to grow. Shoot for the moon and the rest of the process will weed out an overzealous list.

For example, if you are new to growing a flower garden, we recommend starting with a manageable 3-5 flower types. The more you grow, the more complicated it can feel. It’s not worth overwhelming yourself and getting defeated. Get a feel for growing before expanding.

Listed are flower types that can all be started at the same time and will yield simple, but beautiful mixed summer bouquets:

Zinnia, Marigold, Cosmo, Dill

Once you have determined the ideal time to start seeds, the next step is to determine how many seeds to start. This is an important step because starting too many seeds can lead to overcrowding, while starting too few seeds can leave holes in your garden. It's time to draft your garden design!

1. Determine your garden size as seen in the graph above. The example includes a raised garden bed that is 4 feet by 12 feet.

2.Review the growing information for spacing between seeds and growth height. Knowing the height will determine where you place the flowers in your garden. Taller plants display better in the middle as a focal or in the background, while shorter plants are visible in the front or near a border. Note: On the chart, "T" is listed for tallest plants at the top and the flower list descends to "S" for shorter. A spacing of 12 inches was used in between each plant.

3. Determine the number of plants you need based on the size of the space you have in your garden. The design calls for 46 total plants. Once the design in complete, count back how many of each type are needed.

4. Calculate the number of seeds to start: Based on the ideal spacing and the number of seedlings you need, calculate the number of seeds to start. You will also want to consider the germination rate of the seeds, which can be found on the seed packet. It's a good idea to start extra seeds to account for any failures. A general rule of thumb is that 20% of the seeds planted won’t make it to the garden, so account for the loss. If you want 10 plants, start 12 seeds or multiply your desired amount by 1.2. 10 seeds x 1.2 = 12 total seeds. It's always better to plant more than you need!

The size of thecontainers you use for seed starting is important because it affects the health and growth of the seedlings, will determine how much space you need, and reusability. Here are a few factors to consider when selecting pot sizes:

Drainage: Make sure the pots or trays have adequate drainage holes to prevent the soil from becoming waterlogged, which can lead to root rot. We always use a solid tray for bottom watering and place pots/trays into that. Set yourself up for longterm success with a universal system using 1020 trays. See our checklist at the end of this blog for recommended sources/sizes.
Reusability: If you are trying to reduce waste, consider using reusable pots with common sizes to keep your system universal. See the Plannnig Guide at the end for detailed recommendations.
Seed starting space: Knowing the demand of your seed space will let you know if you’ll be able to provide enough light & heat which is critical for their development. If you do not have a sunroom, greenhouse, or enough window space, consider our bulletproof Seed Starting System.
If you have limited space or are working with really small seeds (like snapdragons), consider starting in channel trays, then transplanting to4 or 6 packs. The packsprovide the perfect root ball size and can hold up to 48 plants on one tray.Knowing what your plant goal is for your garden design will help determine the container sizing as well. Download the Planning Guide at the end of this post for a deeper look at sizing and sourcing.

Finally, it's important to make a schedule for your seed starting journey. This will help you keep track of the different flower types start dates and allow you to make improvements the following year. Use the charts made earlier to plug in your frost free date, then count back the weeks to plug in your groups of flowers to start.

Set an alert on your phone so that you don't miss it! Smart phones can even set a yearly alert so that you can 'set it and forget it."

Document your start datesand make future adjustments as needed to the schedule. Light and heat variations can either speed up or slow down growing conditions. You'll need to refine what works best for your conditions.

In a nut, proper planning before starting seeds is key to your seed starting success. Plan now to “set it and forget it” later. By reviewing the seed packets, determining when to start seeds, calculating how many seeds to start, selecting the rightcontainersizes, and making a schedule, you will set yourself up for a successful and enjoyable seed starting experience.

You want to be observing growth and monitoring when to water - not fiddling with start dates. Monitor the growth is where all the good stuff happens and will help you to develop your green thumb quickly.

Happy gardening!

Below is an easy to follow, thoughtful resource to help guide you through the planning process.

INDOOR SEED PLANNINGGUIDE

STEP BY STEP VIDEO TUTORIAL

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FAQs

How To Plan For Seed Starting Indoors? ›

Mid-March is the best time to start many vegetables and annual flowers indoors for transplanting outside once the threat of frost has passed.

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What month is best to start seeds indoors? ›

Mid-March is the best time to start many vegetables and annual flowers indoors for transplanting outside once the threat of frost has passed.

Learn More Now ›

How many hours of light do you need to start seeds indoors? ›

The minimum amount of light is 10 hours. Generally, seedlings need 14 to 16 hours. You can get into the scientific amounts and test it down to the optimal hours and minutes - and some studies do just this. Keep a close eye and see if they seem to be stretching.

How many seeds per hole when starting seeds indoors? ›

Add one seed to each pot or cell. Use the crease of the seed packet or place seeds in a creased piece of paper to help direct the seeds where you want them to go. Sometimes not every seed will germinate. To increase your chances of success, add 2-3 seeds to each pot and thin out the extras once everything has sprouted.

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Do I need a grow light to start seeds indoors? ›

The natural light from a window is seldom enough for good, strong seedling growth. They will usually stretch and lean towards the light and will not produce sturdy plants. Sowing seeds indoors under fluorescent lights is the easiest way for the home gardener to control growing conditions and grow healthy transplants.

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Do I need a heat mat to start seeds? ›

While your lettuce seeds may germinate just fine in an unheated room or shed where the temperatures range from 40-65℉ in the Spring, other gardening staples will not. Tomatoes, for example, rarely germinate below 75 degrees. To start these properly you will need to warm the soil using seedling heat mats.

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Is February too early to start seeds indoors? ›

There are plenty of seeds that you can start indoors in February, and even a few that you can direct-sow outdoors.

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How often do you water starting seeds indoors? ›

Indoor seedlings generally need water every 2-3 days.

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What soil to use for starting seeds indoors? ›

Commercial seed-starting mixes, usually composed of vermiculite and peat, without any true soil, are recommended for starting seeds. They're sterile, lightweight and free from weed seeds, with a texture and porosity especially suited to the needs of germinating seeds and tiny seedlings.

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Why start seeds in small pots? ›

By starting a plant, like a rooted cutting or a seedling, in a small pot, you can ensure that roots populate the entire soil mass fairly quickly and drain it of any excess moisture.

Should you water seeds right after planting? ›

Using a small plastic tub or tray, add in your soilless mix. Then pour in just enough water to saturate it to “wrung-out sponge” wetness. The idea here is that the soil is already moist when you plant your seeds, so you don't have to worry about watering for a few days.

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Can I use a shop light as a grow light? ›

But when you just want to coax a plant to that seedling stage before moving it outdoors to let the warm-weather sun take over, you don't need to use grow lights specifically. In fact, shop lights may actually be a better choice because of the kind of light they emit.

Do I plant the whole packet of seeds? ›

If only a few plants are needed, it is not necessary to plant all the seeds in a packet. Surplus seed often can be saved for a later planting date. Keeping seed dry and cool or at least at room temperature in a closed container is best.