The garden is at rest, but setting up an indoor seed starting set-up prepares small seedlings for their big year ahead. For anyone with the garden bug, this is one of the best parts of the growing process. The colorful catalogs come, the potting soil is purchased, one smells earth again in the thick of dull winter. Instead of the idea of babysitting needy plants, the gardener has the chance to see the tinkering and observing as a joy of anticipation on these short, gray days. For the mother teaching, or enjoying a hobby, it is also something quick, maintainably tidy, and bountifully fulfilling.
Do I Really Need a Indoor Light System?
Yes! For a gardener that does not own a green house, starting seeds inside is the best option for early spring seedlings. Cool weather crops need an early start to capture southern cool weather while it lasts. Crops like peppers and tomatoes take a long time to get to a mature size, and require a wait before warm weather arrives. A gardener can also get a jump on warm weather plants, and prepare successions inside. All of these require a space, warm and well lit to achieve these garden goals.
What are “Leggy” Seedlings?
Seeds that have just emerged are on the hunt for light. It is their warmth and food source, the construct for producing the energy needed to grow. We’re starting seeds inside to give them a boost, ahead of weather and the upcoming growing season. But weak winter light by window isn’t enough, so seedlings lean in search of stronger light. Their stems grow longer as their leaves reach for sunlight. As a result, “leggy” or long stemmed seedlings.
Why are Leggy Seedlings a Problem?
The first leaves to emerge on a seedling are called the “cotelydons”. The next set of leaves to emerge are the “second set” of leaves, and tend to be their full size fairly quickly. Seedlings are often ready for transplant when they are just a few inches tall. But, mature leaves on long, spindly stems will endanger the seedling. Stems snap during transplant, when the wind blows, or with watering.
How to Avoid Beginner Seed Starting Mistakes
Using a light system inside to prepare seeds for the season gives the gardener a head start on spring, and also prevents common seed starting mistakes. And Mom would rather not do anything twice, if she can help it.
- Prevent Leggy Seedlings – plants require proximity to light and heat, and an overhead light provides both. Seeds, however, need to be significantly closer to light than you would anticipate when not outdoors. When seeds are first started, lights should hover around 2-4 inches above the soil. When sunlight through a window is their only light source, plants will grow and reach for light leading to leggy seedlings. A transplanted leggy seedling is harder to support, and commonly breaks with wind.
- Prevent Slow or Uneven Growth – If seedlings are being started indoors by window light, it is common for there to be irregular growth, if any. Very small seeds need ample light to germinate, while very large seeds need additional warmth. Some seeds naturally grow at a more rapid speed and will be inclined toward legginess.
- Support Restarting – In the event that seedlings are neglected (hello life!), or die by other means, seeds restarted will often miss their ideal windows of growth without additional light and warmth to support them. This goes for direct sown seeds as well – in the event of poor germination, bugs or weather, a crop can be restarted under lights and more quickly transplanted than restarting the seeds directly in the ground. If you’re looking to cover mistakes and planting problems, light
Seed Starting Supplies Needed:
- LED Lights – you don’t need specific “grow lights”, you just need some good lights with around 4000 lumens. I typically fix two lights for one shelf on my rack to really cover the entire area with light.
- Metal rack – your lights need something to hang from, and your seed trays need something to rest on. A wire metal rack makes for easy clean up, but any rack will do.
- Paper clips – instead of mounting the chains of your lights to the rack directly with zip ties, consider using paper clips! This allows you to raise and lower your lights as seedlings grow by adding or removing clips.
- Potting soil – now we are on to basic seed starting materials: light, water and soil to grow in!
- Small Watering Can: most seed trays only need an inch or two of water, so a small watering can (or a mason jar in a pinch!) will suffice. The smaller, the lighter, the easier little ones can aid in this seed starting task.
- Seed Trays – I have tried the 72 cell trays, and starting in 4 inch pots, but 12 cell trays are very practical. For the sake of variety in a kitchen garden, or a beginner flower farm, one can begin 1-2 seeds in each cell and have 12-24 plants of each species or variety. It may be hard for one family to eat through 12 cabbages, or the fruit of 24 tomato plants. And, as one one has a hard time choosing between all the shades of zinnias, I appreciate starting 2 colors in one tray…
- Fox Farm Liquid Fertilizer – this one is a bonus, but has really helped with sturdy, well producing seed starts. Once the second set of leaves emerge, adding 1 teaspoon of fertilizer to your watering can is enough to give your plants a boost in color, stem thickness and growing speed.
How Many Hours of Light Do Seedlings Need?
Seedlings need anywhere from 12-16 hours of light, with a period of darkness to rest.
Why Are Seedlings Falling Over?
If seedlings have reached for light, and over grown, it cannot be remedied. But, a good light set up should speedily catch new seedlings up!
When Are Seedlings Ready For Transplant?
There are 5 signs your seedlings are ready, or close to ready to transplant:
- The roots of your seedlings are long, or escaping from their seed tray through the watering hole
- Based on the crop, they are a strong and suitable size for transplant – sporting 2-3 sets of mature leaves, a thick stem, and dark green color.
- They are yellowing, a bright green or dropping more leaves than their cotyledons. This may be a sign that they are overdue for transplant
- The weather and timing of their “dates to maturity”, combined with their readying appearance.
- The soil of the plant is drying out more rapidly, or requires more frequent waterings.
Read More on Seed Starting
Troubleshooting the ins and outs of seed starting may feel like fumbling around for a beginner gardening, but the steps and signs of mistakes are quickly learned. Seed starting is one of those skills that becomes clearer through doing, not perfect planning. If you’re ready to read a little deeper, the posts below explore common seed starting questions and offer steady, beginner-friendly guidance:
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