Seed Sowing and Propagation Course

This was the first of three courses run by the farm to educate staff and volunteers alike.

Growing conditions for seeds

• Storing seeds properly to maintain viability. Some seeds have very good viability, lasting for years, others don’t last more than a season.
• Avoiding overcrowding, this can help avoid disease and competition.
• Tamping down compost to make sure of good contact with growing media and allows a more even distribution of any sieved compost on the top of the seeds.
• Prevent disease by providing good air flow and drainage.
• Covering the seeds to maintain a constant humidity and moisture level.
• Keep seeds warm to encourage germination.
• Turn seeds to keep stems strong – or use foil to reflect the light onto both sides of the seedlings.
• Feed the seeds well, taking into account organic feeds for the farm’s soil association status; using only organic feeds for fruit and veg.
• Acclimatise them to natural daylight.

Reading a seed packet

The information on a seed packet contains, but is not limited to the following:

Plant name–Both the common name, like Bloomsdale Longstanding spinach, and the scientific name, Spinacia oleracea.

Type of plant—Types can include heirloom, hybrid, organic and other identifiers.

Plant description—The description includes basic information on whether the plant is an annual, biennial or perennial and some of its key features. The plant’s history, height and width may also be included.

Packed for date—Seeds are packed for and sold by the current year; however, seeds packed for previous years are usually good to plant for several years.

Planting time—Planting time depends on weather conditions for a specific area. Some packets include hardiness zone maps with a month or a range of months for planting.

Seed packets will also give information on whether to start seeds indoors or to plant seeds outside.

• Start seeds inside according to the packet’s recommendation, usually 6-8 weeks before the average last frost date. 
• Plant seeds outdoors after the soil has dried and warmed to the optimum soil temperature. Planting too soon or too late could be a reason some seeds fail to sprout.

Light needs—The amount of sunlight plants need from full sun to partial shade. Most fruits and vegetables need at least 6 hours of sun every day. Here we need to consider the light requirements and the light available in our polytunnels (including shading from trees etc.).

Row spacing—The amount of space between rows allows enough space for plants to grow without being crowded.

Planting space—Spacing is also critical between individual plants. Spacing may include how closely to plant seeds and how to thin the plants once they start growing.

Seed depth—Use a ruler or other guide and follow seed depth recommendations. If seeds are planted too deep, they may have a hard time reaching the top of the soil.

Days to sprout or germinate—Keep track of germination dates so you’ll know the timing of when plants start to grow. If seeds fail to sprout, replant seeds and they should catch up quickly.

Days to harvest (or mature)—For vegetables, the harvest dates will vary depending on the variety or cultivar. Harvest fruits and vegetables when they’re at their peak and avoid leaving vegetables on plants too long.

Special information—Depending on the seeds and seed company, there may be growing notes, staking information, fertilizer recommendations, suggestions for cutting or harvesting, recipes and other tips for success.

Soil media for seedlings

There are many types of seed compost you can try, but here a few to experiment with.

Watering seedlings

The “water from above” method

This is the most common watering method not only for seeds but also other indoor and outdoor plants. My weapons of choice are a spray bottle and a quart-size watering can.

First, a note on the spray bottle: Buy a good one.  Like any quality tool, it must be comfortable to use in your hand. It should have an adjustable nozzle and a soft trigger. You’ll want one for water as well as separate ones for food/foliar spraying, and if you have to, pest control. Below is an example of a hand pump sprayer (for illustration purposes only).

Second, temperature. Try to use water that’s room temperature or warmer. Cold water can discourage germination and growth. It’s kind of like being forced into a cold shower when you really need a sauna to work in.

2. The “make some moist mixture” method

In this method, the soilless mix you plan to use is “pre-moistened” prior to being put in the growing containers. Using a small plastic tub or tray, add in your soilless mix. Then pour in just enough water to saturate it to “wrung-out sponge” wetness. The idea here is that the soil is already moist when you plant your seeds, so you don’t have to worry about watering for a few days. The only drawback is if you’ve made too big of a batch, you’re stuck with a pile of unused moist soil. Simply place it outside to air dry, or add it to your garden soil.

3. The “water from below” method

While this method takes the longest to moisten the soil, I think it’s the easiest. Here you use a physics property called capillary action, also called wicking. Water is placed in the plastic or metal tray that the seed containers are sitting in. The water is soaked up through the bottom holes and into the soil mix. You only need to fill the tray about a quarter to a third full of water. You don’t want to overdo it, as it will encourage mold or fungus.

You can also use capillary matting to water plants from underneath. Capillary matting is a material that absorbs and holds water, which is then drawn up by the soil in nearby plants. It can be used to create a self-watering system for indoor and greenhouse plants.