Starting seeds at home is a fulfilling part of getting your garden started on the right foot. It is exciting to see the greening of flats before the garden is even ready to receive them and quite a bit easier than one would imagine. When you grow transplants you tend to waste less seed, get more uniform plants and earlier yields, since the plant started its growing cycle before the weather was amenable to its placement outside. These advantages are great motivators for gardeners who all love having the first of whatever is coming on next in the garden!
However, it is good to be aware that not all vegetables lend themselves to transplanting. Root crops like carrots, radishes or beets are usually direct sown and then thinned. Other veggie varieties like corn, cucumbers, summer squash and dill can be sown directly with as much success as a transplant; here the choice is yours. Tomatoes, peppers, broccoli and cabbage are great selections for transplants since they are usually much anticipated crops that will yield earlier if begun ahead of time in a healthy growing environment. Read the directions on your seed packets or consult reliable source material to determine what will be best for each type of vegetable. Since transplants require preparation and work, you may want to plan your transplant ‘menu’ accordingly.
There are many organic soil mixes on the market for everything from houseplants to vegetable plants. For a beginning gardener, buying a mix specifically for seed starting is an easy way to start growing transplants. Use the high quality mix for seed starting in small cells and the more economical potting mix for filling in large containers if you’ll be moving your transplants to pots.
Sowing the Seed
Select your containers and fill them with soil mix. People use everything from egg cartons to newspaper rolled cups, yogurt cups to horticultural flats. All containers must have good drainage and be sanitary. If you are reusing containers seasonally be sure to wash them well and rinse in a 1:4 bleach solution, then air dry. Drainage is important; if kept too wet young plants will be susceptible to ‘damping off’, any of several fungal foes that will decimate young plants easily.
You can also start seeds in unsegmented flats in rows, well labeled, ¼” deep and 2” apart. This allows you to efficiently utilize a heating mat (which greatly improves germination) as well as allowing for culling of poor seedlings upon germination. Cover the germination container with a plastic lid, plastic wrap or cover with a pane of glass to increase humidity until germination occurs. Once seeds germinate you may remove the plastic cover. Upon germination seedlings should be placed in bright light or under growing lights to prevent unnecessary “stretching” – when the stems grow faster than the rest of the plant.
Transplanting or Potting Up
Once young plants have at least their second true leaves they can be carefully removed from their germination flat and transplanted into their bigger more permanent container (i.e. 4” pots for tomatoes, or whatever you have chosen). Once ‘potted up’ a dilute fertilizer may be applied if necessary, dilute kelp or fish emulsion works well (follow the directions for seedlings on the label or half the most dilute amount). If the soil mix does not contain fertilizer liquid fertilization may be done 2 times per week. Be sure to quickly rinse the fertilizer off the seedling leaves or it will burn them.
Transplants still should not be over watered or over fertilized or they will become susceptible to disease. A good way to minimize overwatering/excessive dampness is to water early in the day and allow the plants to go into the night drier. Additionally, pay attention to the outside weather conditions as well as the root development of your plants. Root circling, or becoming root bound, will hamper the ability of your transplants to adapt easily to the garden environment. If the roots are beginning to circle in their containers then it is time to consider getting them into garden soil as soon as possible.
Hardening off is a process by which plants are prepared to manage the harsher conditions of life outside. It consists of decreasing water and fertilizer 1 to 2 weeks prior to transplanting outdoors. This allows the cellular structure of the plant to ‘harden’, literally, the cuticle of the plant hardens to provide protection against the harsh rays of the sun and desiccating winds. Plants should spend some time outside daily prior to planting, be sure to place them in a shady protected place and allow them to adapt slowly. Be attentive to watering since plants outdoors can lose water and quickly dry out. The plants should not be fertilized and will not grow rapidly during this transition. Their energy is being utilized elsewhere.
Once well hardened off the plants are ready to set out into the garden! Prepare your soil well, plant gently and always, always, always water them in (well!). You’ll get the satisfaction of seeing your faithfully tended plants thrive!
Written by Megan Scheider
The New Organic Grower. Eliot Coleman, 1989. Chelsea Green Publishing Company.
The Myth of Permanent Peatlands: “Peat moss is an environmentally friendly organic amendment essential for many horticultural purposes” Linda Chalker-Scott, Ph.D., Washington State University
Potting Mixes for Certified Organic Production. George Kuepper and Kevin Everett, 2004, Updated 2010. National Center for Appropriate Technology IP112.