Seed Starting: Setting the Stage for Success
- Suzanne Sauls
- Mar 20
- 5 min read
First, THANK YOU for making Opening Day of the Seed Library of Laramie County successful! This joint project between the Laramie County Master Gardeners and the Laramie County Library System kicked off the 2025 Growing Season, offering free vegetable, herb, and flower seeds. If you didn’t have a chance to join us, you can still check out seeds from the library’s 3rd Floor, no library card needed.
Second, now that you have seeds in hand, we invite you to join us this coming Saturday, March 22, 2025, from 1:00 pm to 3:00 pm, at Laramie County Community College (LCCC)’s Pathfinder Building, Room 305. Our Master Gardeners continue their “Let’s Get Growing!” Workshop series, this time demonstrating seed sowing techniques, demystifying planting instructions, etc. The event is free, and registration is required (register online at www.lcmg.org). Attendance at prior workshops is not required.
Setting up a seed starting space is simple and rewarding. It extends the growing season, keep bugs at bay, and provide optimal nourishment to your little plant babies. The “perfect” location is anywhere you can control light, temperature, water, and air circulation for your seedlings.
Left: Egg cartons with plastic wrap to retain moisture & improve humidity; Photo: hazelandcompany
Middle: Seed starting setup near west-facing window with grow light hanging from PVC pipe & waterproof heat mat; Photo: S. Sauls
Right: Basement seed station with grow lights; source: Univ of WY Extension
Step 1: Gather Your Supplies. Starting seeds doesn’t require fancy equipment—many everyday items can be repurposed for this task. Essential supplies include seed trays or pots, seed-starting mix, seeds, and labels. Additional tools like programmable power strips, grow lights, heat mats, and oscillating fans may be helpful. Pots can be store-bought or crafted from items like egg cartons, newspapers, or plastic jugs. It’s best to use a soil-less, sterile, light and fluffy seed starting mix to avoid garden soil contaminants that could harm young plants. Fertilizers are not needed for germination as the seed contains all the energy required to sprout and grow until the first set of “true leaves” appear. If you do want to add fertilizer, wait for approximately 3-4 weeks after these “true leaves” appear (or once the seedling reaches at least 2 inches tall), and make it a small, diluted dose (about a quarter of the strength of a full dose for a mature plant). Seed starting mix can be purchased and commercial companies constantly change their products so pay attention to the brand’s ingredients because they can change over time. A recent YouTube video from Epic Gardening compared 8 seed starting mixes for 2025, including a home recipe, and the results were fascinating [1]. As you experiment, recommend looking at the same characteristics they did – cost per use, germination rate, root structure, plant size, and internodal distance. The other option is to make your own. For her seed starting, the UW Laramie County Extension Horticulturist uses a mix of two parts peat to one part perlite (adding more perlite if additional drainage required or propagating plant cuttings).
Step 2: Set Up Proper Lighting. Light is essential for plants, as it powers photosynthesis--the process by which green plants convert carbon dioxide and water into sugars and starches using sunlight. If you notice a “leggy” seedling (pictured below), this indicates it is stretching for light, which weakens its stem. Natural window light is often insufficient, so using supplemental lighting is beneficial. Grow lights with a cool white or “daylight” setting emit blue wavelengths that promote leafy growth, making them ideal for seedlings. Position the lights within 2-3 inches above the plants and adjust as they grow. Remember to turn the lights off at night to give your seedlings a chance to rest. [2]
Step 3: Manage Temperature & Humidity. Photosynthesis slows under freezing conditions and increases as temperatures rise (up to a certain limit). Each plant thrives within its specific temperature range and the seed packet may include this range. Generally, cool-season vegetables germinate best at 55˚F-65˚F, while warm-season vegetables prefer 65˚F -75˚F [2]. Studies show the importance of providing constant warm temperatures during the germination and leafy growth stages of a plant—warmth signals to the seed that conditions are favorable for growth, activating enzymes which breakdown stored food reserves, kickstarting cellular respiration, and improving water absorption rates [3]. Inconsistent or suboptimal temperatures can disrupt these processes, leading to poor germinations rates or delayed growth. Oregon State University Extension conducted an experiment to correlate the number of days to germination and the temperature at which vegetable seedlings were kept. They provided a table (below) identifying the minimum, maximum, and optimal soil temperatures for germination by vegetable type. [4]
As a space-saving technique, recommend grouping seeds with similar growing temperature needs together (e.g., warm-season seeds all in one seed tray), using a waterproof heat mat to provide consistent warmth to help them sprout. You’ll want to remove the heat mat after a majority of your seeds have germinated because prolonged use in the seedling stage can overheat the roots and weaken growth [5]. Dome covers increase humidity and help retain moisture. To minimize algae or mold, remove the domes once 50% of your seeds have germinated.
Step 4: Water Wisely. Water is crucial, but overwatering can be disastrous. Aim to keep the soil moist without making it soggy. Since seeds are often planted near the surface of your tray or pot, gently misting from above is the best way to reach their shallow depth. Once the seeds germinate and roots start growing downward, switching to bottom-watering may be more efficient (but no persistent standing water). As your seedlings grow, adjust your watering routine to prevent root rot (this might mean watering less often but more deeply each time). On the advice of a fellow Master Gardener, I also place a couple packets of dried chamomile tea in the water reservoir—I could not find a scientific article specific to chamomile's effect on seedlings, but did verify chamomile has antimicrobial qualities that have shown to have an anti-infective effect on the growth of fungi and bacteria. [6] After trying this technique for a couple of growing seasons, I did see less seedlings dying from damping off and less fungus gnats swarming around my seed trays.
Starting seeds at home is a practical way to kick off your growing season. By setting up an area that caters to your seedlings’ needs—light, temperature, water, and circulation—you’re giving them the best possible start to thrive. Nurturing seedlings into mature plants is a rewarding way to connect with nature. Happy Growing!
Written by Suzanne Sauls, Laramie County Advanced Master Gardener
References:
[1] "We Tested 8 Seed Starting Mixes, Here’s What We Learned," Epic Gardening YouTube Channel, posted March 13, 2025, available for viewing at https://www.youtube.com/watch?v=TtiNgxs_r4s
[2] "Sustainable Horticulture for Wyoming: A Master Gardener Handbook," University of Wyoming Extension Publication B-1156, 2004, available for download from https://www.wyoextension.org/agpubs/pubs/B-1156.pdf.
[3] "Impact of Temperature and Water on Seed Germination and Seedling Growth of Maize," Khaeim, H.; Kende, Z.; Jolankai, M.; et al.; Agronomy Magazine, 2022, available for viewing at https://repository.qu.edu.iq/wp-content/uploads/sites/31/2025/03/Maize.pdf
[4] "Soil temperature conditions for vegetable seed germination," J.F. Harrington, Oregon State University Extension Service, April 2013 (reviewed 2024), available for viewing online at https://extension.oregonstate.edu/gardening/soil-compost/soil-temperature-conditions-vegetable-seed-germination
[5] "Seed-Starting Heat Mat: When to Turn It Off," Megan Shinn, Horticulture Magazine (online), Feb 7, 2017, available for viewing at https://www.hortmag.com/featured/seedling-heat-mats-when-to-turn-them-off
[6] “Chamomile: A Review of Its Traditional Uses, Chemical Constituents, Pharmacological Activities and Quality Control Studies,” Yun-Lei Dai, Ying Li, Qi Wang, National Library of Medicine, National Center for Biotechnology Information, published 2022, available for download from https://pmc.ncbi.nlm.nih.gov/articles/PMC9822300/.