TOPIC OF THE MONTH: STARTING SEEDS INSIDE

Master Gardener, Jane Faris

WHY START SEEDS INSIDE?

You can get a head start on the growing season and grow varieties that are not readily available at the nurseries. Also, it can be cost effective.

WHAT TYPE OF SEEDS CAN BE STARTED INSIDE?

In general, you ca grow-slow growth non root vegetables such as lettuce, cabbage, broccoli, cauliflower, peppers, eggplant, and tomatoes. Flowers include such annuals as marigold, zinnias, heliotrope, blue salvia, gloriosa daisies, celosia, nicotiana, petunias, and poppies.

Remember to choose vegetables and flowers that are easy to transplant. Also, consider sowing hybrid seeds because they often have increased vigor, better production, and have more disease resistant qualities.

WHAT IS THE PROPER TIME TO START SEEDS INSIDE?

Determine when you would normally plant outside (consider: last frost date, soil temperature and rate of seedling growth). Generally, plant seeds inside 6 to 8 weeks before you plan to transplant them to the garden.

WHAT TYPE OF CONTAINERS CAN BE USED?

There are many types of containers that can be used to start seeds inside. The most economical are recycled containers. Here is a brief list of useful items: margarine tubs, paper cups, newspaper cups, clay and plastic pots, cottage cheese containers, bottom of milk cartons and bleach bottles. New containers include plastic seed trays, peat pots, compressed and peat pellets, just to name a few.

Take note, if you choose recycled containers, take the time to sanitize them. Wash with soap and water and rinse them with a solution of 1 part bleach to 9 parts of water. Sanitizing will reduce the fungi and bacteria population found on recycled containers and hopefully prevent infecting your seedlings.

WHAT TYPE OF SOIL SHOULD BE USED TO START SEEDS?

The best type of soil should have these characteristics: fine and uniform in texture, well aerated and loose, free of insects, disease organisms, and weed seeds, low in soluble salts, and able to hold moisture yet able to drain well.

Remember garden soil is not a good medium to use because it is too heavy, not sterile, and does not drain well.

One mixture that contains the proper elements is the following combination.

1/3 sterilized sand

1/3 vermiculite or perlite

1/3 peat moss

There are many materials that can be used to start seeds. Experience will help you determine which one is best for your inside conditions.

WHAT ARE THE BEST SEEDING STEPS?

  1. Fill container ¾ inch from the top with a moistened soil mixture.
  2. When using a flat, make rows 1 to 2 inches apart. When different seeds are used in the same container, it is wise to plant them in rows. When one type of seed is planted they can be scattered over the surface.
  3. The depth of the seed is usually 2 to 4 times the seed’s diameter.
  4. Extremely fine seeds are lightly pressed into the soil medium and watered with a mist spray.
  5. General rule: seeds other than the very fine seeds should be covered about 2 times their diameter.
  6. Slip seed containers into plastic bags or cover with clear plastic wrap. This will help retain the soil moisture. Watering should not be necessary until seeds have germinated. Remove plastic when seeds sprout to allow air circulation.
  7. Place seeds in a warm location. Generally 65 to 75 degrees is needed.

WHAT IS THE PROPER CARE FOR SEEDLINGS?

Temperature:

Place seedlings in a bright, airy, and cool location. The temperature should be kept at 55 to 60 degrees at night and 65 to 70 degrees during the day.

Lighting: When a bright window is not available, place the seedlings under a fluorescent light. Use preferably two 40 watt cool-white fluorescent tubes or grow lights. Position the plants 6 inches from the tubes. As seedlings grow the lights should be repositioned to keep the lights at the proper distance from the top of the plants. Keep the lights on 16 hours each day.

THINNING: Some plant seedlings will need to be placed into larger containers. Tomatoes, for example, should be thinned to one plant per pot after they get their first set of “true” leaves (those leaves appearing after cotyledons or seed leaves).

FERTILIZER: Use a soluble house plant fertilizer at a dilution recommended about every 2 weeks.

HARDENING OFF: Hardening off is exposing a plant that has been growing indoors to the outside. This process is accomplished by increasing the periods of time the plant is outside. Thus, when the plant is transplanted to the garden it can make the transition with a minimum of shock. In other words, when transplanting to the out of doors, make sure to gradually expose the plant to sunlight.

TRANSPLANTING TIP: Always try to transplant on a cloudy day. On warm sunny days, cover newly planted seedlings with a material (paper, cloth, etc.) folded in a tent design for two to three days. Also, try to not place transplant on windy days.

REFERENCES

Penn State College of Agriculture Sciences

Department of Horticulture

University of California Agriculture and Natural Resources, Publication 3382, California Master GardenerHandbook, 2204.

University of Missouri Extension

Ray R. Rothenberger, Department of Horticulture

University of Illinois Extension, The Plant Palette

Jennifer Schultz Nelson, Unit Educator, Horticulture