The Magic of Seeds Program Recap

Thank you to Karen Prager from the Rugters Master Gardeners of Mercer County for a jam-packed presentation on all things seeds. Starting your plants and garden from seeds can be a very rewarding and satisfying experience, but takes time, commitment, and perseverance. You can also save money by growing your own seeds and grow varieties that may not be available in local nurseries. Let’s jump in and see what Karen has to say!

Know Your Plants and Location

Before you begin the process of growing seeds, it is important to have a solid understanding what and where you are planting. In some case what you want to plant will determine where you will plant, and vice-a-versa if you having an existing garden. Vegetables, flowers (annuals, perennials), and ornamental grasses will all have different requirements in terms of when to sow, where to sow, amount of sunlight, and maintenance. For example, vegetables can range anywhere from 4-8 hours of direct sunlight and while flowers have a similar range, they may also need light during a particular time of day. You can find much of this information in seed catalogs or on the seed packets themselves.

There are many different classifications of seeds that may determine what seeds you wish to buy:

USDA Certified Organic – seeds from organically grown plants.
Open Pollinated – field pollinated/naturally pollinated. Will breed true to type.
Heirloom – Seeds from older varieties and open pollinated with a history.
Hybrid – Joins characteristics from two parents. Will not breed true to type.
Non-GMO – Seeds unmodified by genetic engineering.

Once you have an idea of what you want to plant, it is time to plan where you are going to plant. When picking a place to plant your garden, you should look for the following things:

Full sun, low wind
Fertile, well-drained soil
pH from 6.2-6.8
Near a water source
Few weeds

You can have your soil tested, which will indicate the Lime Requirement Index (buffering capacity, resistance to pH change, if limestone is needed) as well as the macronutrients present (phosphorus, potassium, magnesium, calcium). Once you have a spot picked out, starting mapping out where you want to plant certain flowers/vegetables to ensure you have enough space.

Starting From Seeds

There are 3 main parts of a seed: seed coat (protection), embryo (tiny plant inside) and endosperm (food source). While the seed does have its own food source for it’s initial growth, it will need light (or dark), warm temperature (or cold), water, and oxygen to continue its development. You can provide these elements in many different ways, both indoors and outdoors, but the most important thing to pay attention to is timing. Starting your seeds at the right time is key to ensure that your plants take when transplanted. Know your area’s Last Spring Frost Date (April 29th for Mercer County) and count backwards based on the seed packet; for example, 8 weeks before last frost date in Mercer County will be March 5th. Always remember, “A little later is better than a little earlier.”

If you want to use harvested seeds from last year’s plants, do a germination test. Take 10 seeds and cover in a damp paper towel, placing in a warm area for 4-6 days. Then unwrap the seeds and count how many have roots: 80% germination is good/40% germination is poor. You can always increase the amount of seeds you place in the towel or double/triple up the amount of seeds you plant in a single hole to increase your chances of successful germination.

To help promote root development, you can perform scarification where you soak the seeds for 24 hours then use a knife or sandpaper to gently scar or nick the protective coating. You can also try cold stratification, which essentially tricks the seed into germinating by using cold to break seed dormancy. You can plant seeds in the fall and hope they survive the elements or you can do this indoors by placing seeds in a plastic bag with a moist paper towel, sphagnum moss or sand, and refrigerate for 4 weeks. Be sure to let them sit at room temperature for a couple week before planting.

Starting Seeds Indoors

Many people choose to start their seeds indoors. Regardless of how you grow your seeds indoors, there are two essentials that everyone should follow:

Use cell flats, seedling trays, or pots with drainage holes. You can also use plastic bottles or jugs, but the most important thing is ensuring proper drainage.
Soilless potting mix. Seeds have their own food source and a soilless mixture will help ensure the seed gets enough oxygen. You can purchase pre-made mixes or make your own (1/3 peat moss or coconut coir, 1/3 screened finished compost, 1/3 Vermiculite or perlite).

When starting your seeds, make sure to follow the directions on the seed packet regarding depth and number of seeds per hole. Ensure all of our containers are sterile, using a solution of 9 parts water to 1 part bleach to prevent fungal infections and other diseases. Make sure that temperature is between 65-75 degrees (try a waterproof heating pad) and the seed containers are covered to ensure high humidity. Make sure to keep the containers moist but not wet; pour a little bit of water into a tray and let the soilless mixture soak it up. Also, make sure to dump any standing water. To encourage healthy air flow, you can use a small fan to help circulate the air. Do not put them under direct lights yet!

Once the seeds start to emerge, remove the heating mat (if used) and transfer them to a well lit area, using grow lights instead of a southern-facing window. As they start to develop true leaves, move them into stronger light, keeping the light 2-3 inches above the seedlings. Make sure to remove any coverings, fertilize with a water soluble solution, and only water after they dry out a bit. You can continue using a fan on the lowest setting to remove built-up carbon dioxide and increase oxygen in the soil.

Beyond Seedlings

Once your seedlings are established, you can start pricking them out. A few hours before starting, moisten the soil. Next, pick out your healthiest sprouts (fewer than 5 leaves) and carefully remove them by gently prying out each seedling, pulling from the leaves rather than the stem. If seedlings are too crowded or there are weak ones, you can use scissors to thin them, trying not to break the roots of the healthy seedlings. Immediately transplant them into new pots without any fertilizer. Ensure they are watered and move them into a cooler place at night (between 55-60 degrees). As the seedlings continue to grow, ensure that artificial lights are raised to keep within 2-3 inches of the tops of the plants. A week before you transplant the seedlings outdoors, they need to harden off. This consists of gradually exposing the seedlings to outdoor conditions, for about 3-4 hours a day. Try to find a place that is generally shaded and free of wind. Hardening off will help strengthen the cell walls and stems while also stimulating root development.

Now that your plants are ready to be transplanted outdoors, it is important to first make sure the soil is ready. Make sure that is it moist, weeded thoroughly, and the holes are amended with compost. Try to transplant early on a warm, overcast day as this will help give the plant’s roots time to settle in. After the seedlings are transplanted, make sure to soak the soil around the seedling and fertilize with phosphorus if needed. Sit back and watch your hard work come to fruition, remembering to water and maintain as directed on the seed packets.

Due to the pandemic, the Master Gardeners of Mercer County’s HelpLine is unavailable so if you have any questions, please email Margaret Pickoff, mpickoff@mercercounty.org, or Karen Prager, kprager@gmail.com. Please visit their website, https://mgofmc.org/, for a variety of helpful resources, including Tip of the Month, talks, articles, and other resources. You can view a recording of the program at https://youtu.be/brJ1w7ibpow and download a copy of the handout with live links at https://www.njstatelib.org/wp-content/uploads/2021/02/Magic-of-Seeds-Handout.pdf.