Seed Starting Basics
Growing from seed is so much fun, very rewarding and is one of the best things you can do for you and your family. Starting seeds indoors under controlled conditions, with no aggravation from weeds or weather, allows you to get a good start on the season!
Seed Starting Soil Mix – Choosing the type of soil can be a critical part of your seed starting process. You do not want to keep your new seedlings in wet heavy soil. It is best NOT to use the soil from your garden as it is often too dense and provides poor drainage. If you want to buy your soil mix commercially, the best soil to use is a soil-less mix, that is specifically made for germinating seeds. You can also make your own seed starting mix!
Here is an easy recipe you can use! Just mix these ingredients together:
4 parts compost
2 parts coir or peat moss
1 part vermiculite
1/2 part perlite
Planting Containers – You can use just about any container to start seeds as long as it is at least 3″ deep to allow for root growth. You can use peat pots, eggshell cartons, plastic trays, homemade paper pots, recycled plastic containers or trays, or anything else that can hold some soil! All containers should have holes in the bottom for drainage. Also, all seed starting containers need to be very clean to avoid disease and it is wise to disinfect before using.
Temperature – The general rule for seed starting is start seeds warm but grow seedlings cool. Don’t try to germinate your seeds on the windowsill. The outdoor temperatures will make this area too cool. Most seeds are genetically programmed to germinate only in warm soil. You can keep the seed trays consistently warm by placing them on top of a water heater or refrigerator. Fluorescent lighting or heat lamps also can keep the soil warm. If your area is quite cool, a seedling heat mat may be your best option. Commercial greenhouses use both lights and hot water heating systems to keep seed trays warm.
Moisture – Seeds need to be constantly moist in order to germinate. Do not let the growing mixture dry out or, equally as important, get too wet. Moisten the growing mix thoroughly before sowing the seeds. Stir the mixture with your hands to distribute the moisture. After the seeds are sown, place a humidity dome or plastic wrap over your container to slow evaporation. Check every day for signs of germination and remove the cover as soon as you see a sprout so that the air can circulate around the emerging seedlings. You can water your seedlings evenly by using a spray bottle. Avoid watering with really cold water.
Light – Make sure to provide lots of light for your seedlings! Lack of light is probably the number one reason people have lack of success and get discouraged as seedlings grow. Seedlings will stretch and get “leggy” in weak light and will have weak stems and often a pale color. Seedlings need 14 – 16 hours of light from the moment they germinate. They also need at least 8 hours of darkness to process their food and grow. Growing seedlings on a windowsill is not recommended, but if it is your only option, turn the containers daily so they don’t have to stretch and reach for the light. You will know if your seedlings need more light if they are pale and weak. Fluorescent lighting or grow lights are your best option and using a full spectrum light bulb. Get your plants as close to the light as possible by putting the lights on adjustable chains keeping them 2 – 4 inches above the tops of seedlings. Move the light fixtures up as the seedlings grow. Adding artificial light can also help keep seedlings warm.
Transplanting – If you did your planting in individual containers, transplanting is not necessary before you set them outside. Seedlings in seed flats need to be transplanted into 4 inch containers by the time you have 4 true leaves. This will give your seedlings more room to grow, stimulate the feeder roots and improve ventilation. To transplant, hold the seedling by it’s leaves, not the delicate stem. With a butter knife, spoon or fork, gently cut around the seedling root and lift up. Place into a pre-moistened container, slightly deeper than they were in their flats. Firm the soil around the seedlings, and water immediately.
Fertilizing – After transplanting, fertilize once a week with an organic fertilizer. We recommend a low concentrated mix of fish fertilizer. After about 3 weeks you can start fertilizing at full strength. Over- fertilization can result in leggy seedlings. If your seedlings are starting to look leggy, pinch back the growing tips to promote more branching. This can be repeated every week or so to promote compact, bushy plants.
Hardening off – Hardening off is basically getting your small plants ready to face the great outdoors! At least a week before you plan to set the plants into the ground they need to gradually get used to the sun, wind and various outdoor temperatures. A cold frame, which is a sheltered unheated box with a translucent cover is the best means for this transitional period. The lid can be gradually raised to expose the plants to more sunlight. If you don't have a cold frame, you can also use row covers or you can place your plants in a shaded, sheltered part of your garden for a few hours each day, gradually moving them into more sun. These unprotected plants will have to be brought back indoors each night unless you know it is going to stay above 50°F all night long.
Things to watch out for
Insects – spray insecticidal soap on spider mites, aphids or whiteflies as soon as they appear.
Dampening Off – This is a fungus that attacks the plant at the soil line. Making sure the seedlings have good air circulation as well as making sure you don’t over-water, will also help prevent this. Sprinkling a bit of sphagnum moss around seedlings has also proven to help this disease.