Seed starting: Getting a head start in the garden

Gar­den­ers who are anx­iously await­ing spring and eager to get their gar­den planted can get a head start by start­ing seeds indoors. Many home­own­ers head to the local nurs­ery to pur­chase plants that can be trans­planted directly into the gar­den. How­ever, with some extra effort, it is pos­si­ble to save money and grow your own flow­ers and pro­duce from seed.

You can scour seed cat­a­logs dur­ing the cold win­ter months, select­ing the vari­eties you want to grow with­out being lim­ited to those few avail­able in the local gar­den cen­ter. This is an ideal oppor­tu­nity to exper­i­ment with heir­loom vari­eties. You can also select new cul­ti­vars that are resis­tant to com­mon gar­den pests. The back of the seed packet gen­er­ally will tell you what year the seeds were packed for, plant­ing depth, the num­ber of days until ger­mi­na­tion, when to start the seeds indoors, and other valu­able infor­ma­tion. Accord­ing to Diane Relf and Eliz­a­beth Ball of the Vir­ginia Coop­er­a­tive Exten­sion, Vir­ginia Tech, and Vir­ginia State Uni­ver­sity, only 65 to 80 per­cent of the seeds are expected to ger­mi­nate in the first year. This per­cent­age declines in sub­se­quent years.

To grow the seeds, you will need to pur­chase a seed-starting kit or assem­ble one your­self. This includes a solid plant­ing tray with ade­quate drainage and a clear plas­tic cover. The tray can be set in a sunny win­dow, but for more pre­dictable results, you can place flu­o­res­cent lights directly above the tray. Do not use incan­des­cent lights as they project too much heat.

Charles Glass is a Delaware County Mas­ter Gar­dener Vol­un­teer who grows most of his plants from seed. He also sells his pro­duce at the Sun­bury Farmer’s Mar­ket. He rec­om­mends build­ing, or pur­chas­ing, a frame to hold sev­eral trays with flu­o­res­cent shop lights hung on chains above the trays so their height can be adjusted as the plants grow.

For best results, use a seed-starting medium, instead of pot­ting soil. Don’t for­get to use plant mark­ers to label the seeds, includ­ing the date the seeds were planted. You should also keep a com­plete record of the variety’s progress through­out the grow­ing sea­son, so you will know what, if any, issues were encoun­tered and whether or not to plant that cul­ti­var again.

Four crit­i­cal fac­tors affect ger­mi­na­tion: water (mois­ture), light (or dark), oxy­gen and heat.

WATER: prior to plant­ing, Mr. Glass mixes up the seed-starting mix­ture in a bucket so that it’s damp, not wet or dry. The mix­ture is trans­ferred to a tray, the seeds planted, and the cover placed on the tray. Ide­ally, the tray will not need to be watered again until the seeds ger­mi­nate. This is the most crit­i­cal time for the plant­ing medium to have the proper amount of mois­ture. Use your index fin­ger to judge whether the soil is damp or if it needs water. If the envi­ron­ment becomes too wet, remove the cover.

LIGHT (OR DARK): The seeds should be planted as indi­cated on their pack­age, which is gen­er­ally at a depth twice the seed’s diam­e­ter. Very small seeds are gen­er­ally pressed into the sur­face of the medium. The tough seed coat of some seeds, includ­ing pars­ley, must be scar­i­fied, or bro­ken, before plant­ing, so that water can pen­e­trate the seed and the ger­mi­na­tion process can begin.

OXYGEN: The medium in the tray should be lightly tamped, enough to keep the seeds in place, but not enough to elim­i­nate the oxy­gen the seeds need to ger­mi­nate and grow. Seeds can be planted in small con­tain­ers or cell packs and then trans­ferred directly into the gar­den, elim­i­nat­ing the need to trans­plant small seedlings.

TEMPERATURE: A seedling heat mat can be placed under the tray to keep it at the cor­rect ger­mi­na­tion tem­per­a­ture. This mat should only be used until the seeds pop up. The 2010 Ohio Veg­etable Pro­duc­tion Guide, which is avail­able online at ohioline.edu, con­tains a ger­mi­na­tion and grow­ing guide for veg­eta­bles and herbs. It lists the opti­mal ger­mi­na­tion tem­per­a­ture for each crop.

After the seeds ger­mi­nate, the plas­tic cover must be removed. The plants need air cir­cu­la­tion and light to grow. Mr. Glass rec­om­mends using flu­o­res­cent shop lights above the plants for 16 hours a day as a lower-cost alter­na­tive to more expen­sive lights made specif­i­cally for seed start­ing. He also sug­gests water­ing the trays from the bot­tom, so avoid dis­turb­ing the seeds.

When the seeds sprout, a pair of cotyle­dons, or oval-shaped seed leaves, emerges first. They are fol­lowed by true leaves, which look sim­i­lar to the leaves on the mature plant. Then the plants should be trans­ferred from the tray to small con­tain­ers or cell packs. Mr. Glass min­i­mizes expenses by using recy­cled plas­tic con­tain­ers, instead of peat pots or paper cups. At this point, you should start apply­ing liq­uid fer­til­izer weekly. Keep the plants watered and, as the seedlings grow, adjust the lights to stay 3–6 inches above them.

When it is time to trans­fer the plants to the gar­den, they should first be accli­mated to the out­doors by keep­ing them in an unheated area of the house for sev­eral days. Then, to min­i­mize stress on the plant, put them in the ground on a cloudy day or in the evening, not in the mid-day sun. Some crops, such as toma­toes and pep­pers, are sen­si­tive to cool weather and should not be planted until the soil is warm. Some other crops, includ­ing car­rots, radishes, and let­tuce, pre­fer the cool weather. They can be planted as soon as the soil can be worked.

For more infor­ma­tion on grow­ing plants in Ohio, visit Ohioline.edu.

Nancy F. Traub is an OSU Exten­sion Mas­ter Gar­dener volunteer.

Posted by Master Gardener on Jan 28 2012. You can follow any responses to this entry through the RSS Feed. Comments can be made below.