Seed starting guide
By David Huebel
There’s a lot of information in books and on the web for starting seeds and almost as many different methods. We’re not attempting to recreate all of that detail here or say that this is the best method – this document is just something of a diary of experiences and hopefully will help you get started or make improvements to your process. The primary message is to not be intimidated – you’ll learn more each time you try, and as with most endeavors, we learn best through our mistakes.
Below you’ll find a list of equipment, the steps for starting seeds, some photos of the process and a list of resources. Note that a great source of information for specific seeds is right on the seed packet. This includes optimum soil temperature, planting depth, and days to germination. Let the seed packet overrule anything stated here.
Seeds can be started year round for continuous planting in the garden but the two primary times are January for spring gardens and July for the fall – i.e. about 8 to 10 weeks before transplanting outdoors (generally a week or two longer for herbs). Aside from the varieties you plant, the primary differences in starting seeds for the 2 times of year are keeping the soil warm enough in January for spring starts and cool enough in July for fall planting.
The primary supplies and considerations for starting seeds are:
- Space – plan ahead for how many starts you want
- Moisture – keep the soil evenly moist
- Temperature – soil and ambient
- Light – sun or artificial
Optional equipment includes heating mats, lights, and a plant mister or watering wand. The equipment is easy to find and relatively inexpensive (refer to sources at the end of this document). Following are additional details on the supplies:
Containers: Anything that will hold soil and provide some drainage will work fine – for example: 4 inch plastic pots (used plastic pots are freely available at most nurseries) and egg or milk cartons
Soil: Good, loose soil is very important for seedlings. Any obstructions (e.g. twigs, clumps, rocks) to the sprouts will slow them down or stop them altogether. You can mix your own, buy a seed starting mix (e.g. Lady Bug Germinator), or use a quality potting soil (e.g. GeoGrowers Thundersoil, Lady Bug Vortex, or The Great Outdoors Blend). There’s additional information on-line, but most “home-mixes” include one or more of the following:
- sifted compost
- sifted leaf mold (decomposed leaves)
- coir (coconut fibre)
A high nutrient content isn’t essential for seeds to germinate (seeds contain what they need). However, after germination, nutrients are needed for good root development and growth and should be added to the transplant mix and/or through supplemental fertilization.
Seeds: Organic seeds can be either heirloom or hybridized. Heirloom seeds are open pollinated and therefore can be saved from your plantings (a great next step in your gardening experience that we’ll cover in a future workshop). Hybridized seeds can still be organic but can’t be saved since the seeds produced from your plants may not match what you’re growing. Non-organic seeds may contain fungicides or other elements you should keep out of your garden.
Note that some seeds (e.g. beans and okra) germinate much faster if soaked for an hour or 2 prior to planting in a solution of water and seaweed or compost tea.
Heating Mats: Useful for keeping soil temperature at appropriate levels when starting spring veggies in January. These are available at local nurseries or on-line.
Lights: Light is essential for good plant growth – there are a variety of options at a variety of price points. For example: 1 to 4 ft hanging, fluorescent shop lights with 1 cool bulb and 1 warm bulb. Special grow lights also work well but are more expensive. A sunny window or outdoors for fall starts can also work, but artificial lights are much easier to control. For example, a sunny window needs a good 8 hours of sun per day, and care must be taken outdoors for fall starts that plants don’t get too hot.
Depending on available space and how many starts you want, you can start seeds in the container they’ll stay in until moving to the garden or start multiple seeds in a container and later transplant to individual containers. If you’re leaving plants in the same container, plant a few extras to ensure germination.
- Fill a container 1/2 inch from the top with a loose seed starting soil – it’s best if the soil is slightly moist. Tamp the pot lightly on a hard surface, but don’t pack the soil.
- Place seeds on the surface
- Top with ⅛ to ¼ inch of soil depending on the planting instructions for your seeds
- Water gently – preferably with a mister, or if outdoors, a water wand facing upward (let the water flow gently down on the containers)
Moisten the soil daily to avoid letting it dry out. Light will be needed as soon as the seeds start sprouting – this is usually within a few days. The lights need to hang 2-3 inches from the top of the plants and remain on for 12 hours/day (plants also need the dark cycle). The height of the lights will need to be adjusted as the plants grow.
When the second set of leaves (called the true leaves) appear (usually within 2-3 weeks) , the starts are ready to transplant into individual 4 inch pots or thin to 1 plant per pot if you’re not transplanting. Note that if transplanting, it’s best to handle the tender sprouts by the leaves and not the stem. The plant can survive a broken leaf better than a damaged stem.
The starts should be ready to go in the ground in another 2 – 4 weeks. If you started your seeds indoors, some outside time (hardening off) is needed before transplanting them in the garden.
Here a few photos to show the process in action and describe a few of the steps in more detail:
Fill pots to about half an inch to an inch from the top with a moistened seed starting mix. Then place seeds on top of the soil – up to 20 can be started in a 4 in. pot and later transplanted to individual pots.
Alternatively, purchase a seed starter tray, which is designed for one seed per slot. After plants form true leaves, they can be transplanted to 4 inch pots.
Whether starting seeds in pots or trays, cover the seeds with soil to the depth specified on the seed packet. Then water gently until the soil is thoroughly moist.
Below is one possible transplant growing setup using a relatively inexpensive plastic greenhouse available online. The seeds can be started just as easily indoors or in a garage, but the soil temperature has to be at least 70 degrees for most Spring veggies. Rubber seed starting mats can raise the soil temp 10 – 20 degrees above ambient. The lights need to hang just above the plants (about 2 inches)
Another indoor growing option is to hang grow lights under a table. Or for a small transplant growing project, try a cardboard box setup as shown below, which makes use of a shop light and a fluorescent bulb
The cucumber seedlings below are ready to move to individual pots. All you need are containers, pots, a rich, loose potting soil and something to pull the soil back to make room for the plant (e.g. a craft stick or spoon). Fill the pots to about a quarter of an inch from the top.
Loosen the soil around the roots and gently remove the starts from the starter pot. It’s best to grab the plant from the leaves and not the tender stem. Using something like a spoon or popsicle stick, pull the soil back in the receiving pot deep enough for the roots. Set the plant in the hole and press the soil around it.
That’s all there is to it – the transplant is now set up in its new home until planting time in a few weeks. Water gently to keep the soil evenly moist and keep adjusting lights so they’re always just a couple of inches above the plants
Following are some local and online resources for gardening supplies including everything you need for starting seeds:
The Natural Gardener – http://www.naturalgardeneraustin.com/
Brite Ideas – http://bihydro.com/
The Great Outdoors – http://gonursery.com/
Barton Springs Nursery – http://www.bartonspringsnursery.net/
Johnny’s Seeds – http://www.johnnyseeds.com/
Renees Garden – http://www.reneesgarden.com/
Seed Savers Exchange – http://www.seedsavers.org/
Seeds of Change – http://www.seedsofchange.com/
A number of local garden centers including, The Natural Gardener, Brite Ideas, and The Great Outdoors have informative workshops periodically (some every weekend) – check their websites for schedules. Austin Organic Gardeners is a gardening club that meets monthly at the Zilker Garden Center and is a great resource for information as well. Check their website for meeting information and schedules – http://austinorganicgardeners.org/.