Start seeds indoors for a jump on the growing season

LED grow lights. Photo: 'GOPR0892' BY CC jalexartis--PRO Account since June 2006

LED grow lights. Photo: ‘GOPR0892’ CC BY  jalexartis – PRO Account since June 2006

In the upper Midwest, it is crucial to start some of our fruit and vegetable seedlings indoors. Here at Heart and Soil Farm in North Dakota, our growing season is short (roughly Mid-April through early October) and you never can tell when spring will arrive. We have what we like to refer to here as Weather— with a capital “W”.

Everyone talks about the weather here; people watch the news just for the weather. If you ask a Midwesterner about their vacation, they will give you a weather report first and foremost because weather, no matter where it is occurring, is worth discussion.

Of course, when your temperature spread can run from -40 to 95 degrees, you can see why. I think Midwesterners are quiet and stoic because they know who is in charge: Mother Nature.

How does a CSA (Community Supported Agriculture) operate in this place of frozen winters and unexpected springs? Planning and indoor growing. And only shedding a few quiet tears when spring decides to be two months late.

Healthy, hardy plants

Starting seeds indoors can give you a jump on the growing season anywhere, as very few of us live in places where the temperature ranges only a few degrees throughout the year.

Starting seedlings indoors also allows you to control the environment when plants are at their most vulnerable. Healthy seedlings are better able to withstand pests, temperature fluctuations and water shortages (very common these days in California).

The most common factors that stress out the plants on our farm are: late spring, temperature fluctuation, wind (North Dakota is a windy, windy place), pests and rainfall fluctuation.

We also have to worry about chemical drift from the surrounding conventional farms. Healthy, hardy transplants are much more able to handle these stressors than plants using all of their resources to sprout and start growing. An added bonus to setting out bigger, hardier plants is that they shade out weeds faster.

What you’ll need

So, how does one start seedlings indoors?

With a little prep work and a few items, you can be on your way to getting that garden ready for the growing season without spending a small fortune on a heated greenhouse.

What you need:

  • Containers and a tray to place underneath
  • Potting soil
  • Grow lights
  • Water
  • Seeds
  • Temperature-controlled room

You can get as simple or as fancy as you’d like with these items. We have a room of grow lights hung on shelves, but we start hundreds of plants each season that go in on a rotating basis to supply our CSA. We also make our own potting soil and have separate temperature control for this room.

For home gardeners, however, this might be as simple as a few containers, some store-bought potting soil and a grow lamp in a warm spot in your living room.

Tip: Make sure you have enough potting soil to completely fill all of your containers, as they hold a lot more soil than would seem possible.

Potting soil and grow lights

If you start a lot of seeds indoors, it’s worth making your own potting soil as it is often cheaper and you can control what goes into the mix. (You can then also boast about how your homemade potting soil is superior to the store-bought stuff, causing eye-rolling from your friends and family).

If you are a DIY-er, here’s how to make your own grow light box. (The nonprofit Growing Hope has many great online garden education resources.)

Otherwise, you can find pre-made fixtures or even install grow lights under your kitchen cabinets.

A simple grow light setup. Photo: '2010.03_diy grow light' CC BY di.wineanddine

A simple grow light setup. Photo: ‘2010.03_diy grow light’ CC BY di.wineanddine

Grow lights are special bulbs which are full-spectrum. The bulbs are referred to as T5 or T8 bulbs. It is not a traditional light bulb.

Please also make sure your light fixture is the correct kind. You do not want to create a fire hazard in your home. Grow light fixtures are curved to force the light downward toward your plant, which helps trap the light and heat. Investing in a quality fixture is important for your safety.

Now that you have gathered all of your equipment – let’s get started!

Starting your seedlings

Establish where you are going to start your seedlings and prepare the area. Make sure it is warm at all times (perhaps by a heater, in a spare room or by a south-facing window) and is in a place where it is OK if you spill some soil or water. (So not in the window nook on your mother-in-law’s hand-sewn quilt that she looks for when she visits.)

Ross Lockhart planting seeds in containers. Photo: Amber Lockhart

Ross Lockhart planting seeds. Photo: Amber Lockhart

Read your seed packets. They have helpful information on planting and timing. You want to make sure you are timing your planting to coincide with when the plant should be set outdoors.

Allow an extra 2-5 days to “harden off” your plants before transplanting in the garden (more on this later) before they go into the ground. Count this as “indoor time.”

Set up your equipment

Set up your grow light. The light fixtures can be purchased online or at home garden centers. If you get a lot of sunshine and can set the plant close to a window, give it a try. But it may take longer for your seeds to germinate or may not work at all if you live in an area with few spring daylight hours.

If you try starting seeds in a window without a grow light, make sure to rotate the plant as it will bend to reach the light and you want it to grow straight up.

In a bucket, mix your potting soil with enough water to form a damp mass. You don’t want the soil to be runny, but it should have the consistency of wet sand and should stick together in a ball in your fist. This will give your plants some much-needed moisture when the seeds go into the potting soil.

Place the potting soil into the containers, and don’t be stingy. You want to gently press it down a bit and get the container full, as the plant roots need room to grow. If it seems too dry, water the potting mix before placing the seed into the soil. Reserve a little potting soil to place over the seeds once planted.

Following the seed packet instructions, making an indentation in the potting soil to the correct depth. Don’t get too hung up on the depth; it doesn’t need to be perfect, but try to get close to the recommended depth. Sprinkle some of the extra potting soil over the top (just enough to cover seeds). Moisten the soil and put the containers onto a tray below the grow lights.

For some plants, we place two seeds into the container and thin when the seedlings emerge, especially if we are using older seed.

Heart and Soil's youngest farmer helps keep the seedlings watered. Photo: Amber Lockhart

Heart and Soil’s youngest farmer helps keep the seedlings watered. Photo: Amber Lockhart


Place your newly planted seeds under the grow light and turn that baby on! Your lights will stay on 24-7 until you are 1-2 weeks away from hardening off the plants. When you hit this period, you will mimic the sun and turn the lights off at night and on again in the morning.

The plants lose heat when the lights go off, so you want to have robust seedlings before you deprive them of light and warmth. They grow faster this way.

Like us, plants need periods of darkness to rest in order to thrive. You can go the other route and follow the sun with your lamps but it will take longer and you need to make sure your room is warm enough. We do not do this as we have a short growing window and want to get things moving quickly.

Now grab yourself a glass of your favorite beverage and sit back, knowing that for a moment or two you have a leg up on Mother Nature.

Tip: A word of caution: If you have cats, you need to have a plan to protect your seedlings so they do not turn into a 24-7 kitty buffet. Trust me on this.

Cats will help themselves to your seedlings! Photo: 'New in the 2012 Garden' CC BY Chiot's Run

Cats will help themselves to your seedlings! Photo: ‘New in the 2012 Garden’ CC BY Chiot’s Run

Check on your seedlings every day and water as necessary. These seed babies are your responsibility now so they must be kept warm and moist, but not water-logged.

Remember – light, water and heat will grow your seedlings into healthy, robust plants.

Hardening off

About 2-3 weeks before you put the seedlings outside, begin to mimic the sun and turn the lamp off at night. Remember to turn it on again in the morning!

Then 1-2 weeks prior to planting your seedlings in the ground, you will start a process called “hardening off.” This simply means you are going to get your pampered indoor seedlings accustomed to being outside in the elements. Some people skip this part, but for us it is necessary as our plants are going into the hostile North Dakota weather – we’re concerned mostly about the wind.

Don’t choose an unusual weather day to start this, such as during a hurricane or hail storm or when it’s 100 degrees outside. If possible, pick a mild day.

For the first few days, put your plants outside in a shady spot, then move them inside in the evening. Then move them outside into partial shade during the day (inside again at night) and finally full sun (or whatever sun your garden gets) and keep them out overnight. Watch the plants carefully for stress, such as wilting. Some stress is natural, as they are getting used to a foreign environment.

Keep the plants well watered. If the weather acts up during this process, you can put the plants in the garage with the door open to offer them some protection.

Time to plant

Once the plants have acclimated to the outdoors, prepare your garden for planting.

Please remove the seedlings carefully from their containers. Expect some transplant shock the first few days after being put into the soil. If you’ve ever moved from one city to another, you’ll know how they feel. It takes some time to adjust to the locals and the new food. When we moved to England for grad school, imagine my surprise as I witnessed people putting canned corn on pizza! That took some time to get used to. So give your plants some time to adjust.

We put the transplants in with all of its potting soil to give it some room to grow in a familiar environment. Think of it like a baby blanket – something comforting. Keep the plants well watered once transplanted into the garden.

Now grow, baby, grow!

Amber Lockhart, master gardener

Amber Lockhart is a master gardener and co-founder of Heart and Soil Farm in Grandin, North Dakota.

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