Jump Start Your Summer Vegetables
Starting Seeds Indoors

By Bob Mulvaney, Master Gardener

While we are still in the grip of winter, why not get some of your summer vegetables started so they are ready to go outdoors when the weather warms up?  Why you may ask, should I do this?  Why not just buy seedlings from my local nursery to transplant?

Well, if you want earlier harvests, greater variety, stronger and healthier seedlings, to save money and more satisfaction and enjoyment, then read some more.

Choosing Your Seeds

Locate and peruse almost any of the seed catalogs which are available to the public.  Try different varieties of tomatoes, peppers, or squash, which seem intriguing to you.

This is a good time to try something you have never had before in the garden.  If you cannot locate a seed catalog, go to your local nursery and purchase your seeds.  Most nurseries provide many more different varieties of seeds than they do vegetable transplants.

Containers and Soil

You can also purchase seedling trays at you local garden center, but why not recycle your own containers.  Egg and milk cartons, disposable aluminum pans, yogurt containers, peat pots, and/or pellets will all work.  Remember to clean them well by using a 9-1 part solution of water (9 parts) to chlorine bleach (1 part) to sanitize your containers.

Your potting medium can be store bought (look for seed starting mix) but you can also make your own using equal parts of commercial potting soil, perlite and/or vermiculite, and peat moss (make sure it is completely moistened).  This will generally be cheaper especially if you are planning a large garden.

Getting Your Seeds Started

Timing is very important when starting your seeds indoors.  Knowing the last expected date of frost in your area is crucial.  For those of you living in San Luis Obispo or on the coast, St. Patrick’s Day, March 17, is the safe planting-out date.  North of the Cuesta Grade and in inland areas, May 1 is a safe date.  Do not put tender seedlings outside before these dates.

Your Seed Sowing Checklist

Gather Your Equipment - Find, buy, or collect your containers, planting mix, seeds, watering can, labels, and markers (for labeling).

Prepare a Work Space - Choose a spot which allows you to spread out.

Review Your Seed Packets - Review the information on the seed packets.  Note things such as days to germination.  Prepare your labels before you sow, particularly if you are doing a number of varieties of the same vegetable.  Labels can be popsicle sticks or store bought.  The important thing to remember is to label all your planting containers.

Prepare Your Containers - Put your planting medium into your containers.  Make sure the medium is pre-soaked, but not real wet.  Prepare the Seeds - Pre-soaking may be necessary for some seeds.  Tomato, celery, parsley, and beans can be soaked for a few hours prior to planting.  Some seeds, like Morning Glories and New Zealand spinach will benefit from scarifying.  This involves nicking the seed coats with a knife or file.  Check the seed packet for special instructions.

Plant the Seeds - If you are using small containers, two seeds per container is suggested.  The weaker of the two seedlings can be pulled out later.  If you are sowing in flats, either scattering or rows will work.

Cover the Seeds - Cover the seeds with a fine layer of planting medium.  The general rule is to cover the seeds to a depth of three times their size.  Seeds which should not be covered with soil should be noted on the seed packet instructions.  Lightly compact the covering soil so the seeds have soil all around them, which will help insure good germination.

Cover and Set in a Warm Place - Use a plastic sheet or bag and set your containers in an area that receives warm but not hot temperatures.

Factors That Influence Germination

The condition of the seed, water, air temperature, light, and soil conditions effect the germination of your seeds.

Water - First, water softens the seed coat so the root can emerge easily.  Then it combines with stored food to form soluble forms of nourishment for the seed.  As a general rule, keep your medium moist but not overly wet.

Temperature - In general, seeds need warmer temperatures to germinate than they will later need when they grow into plants.  Extremes of heat and cold inhibit germination of most kinds of seeds.  The most favorable germinating temperature for vegetable seeds started indoors is between 70 and 80 degrees Fahrenheit.  Remember that is soil temperature.  A soil heating cable has been most helpful to me in maintaining a constant soil temperature to aid the germination process.

Light - Most vegetable seeds are indifferent to the amount of light they receive during germination.  Your seed packet instructions should inform you if this is not the case.

What Your Seedlings Need

Light - As soon as the seeds have germinated, they must be given adequate light either from a fluorescent tube or from the sun by way of a house, greenhouse, or cold-frame.

Artificial Light - Reports of results from growing plants under fluorescent light at the North Carolina State University and Cornell University indicated that:

·         Plants do well under a variety of tube combinations

·         Special plant-raising tubes are not necessary for starting plants.

·         Best results are often obtained by mixing tube colors.  For example, using one warm and one cool tube in each fixture.

If possible, use a 48 inch fixture with at least 2 tubes of 40 watts and a reflector attached to the fixture.  Remember, seedlings generally need more intense light than mature plants.  Keep your seedlings close to your light source, 2-3 inches.  Raise your light as the seedlings grow.  Plan on having your light on for 16 hours per day.  An automatic timer will assist in this process.

For those of you who do not want the expense of artificial lighting, find a sunny corner in a garage, barn, or outbuilding where your seedlings will get a substantial amount of sunlight.

How to Water and Fertilize Your Seedlings

Use tepid water on seedlings.  If your water is chlorinated, let it stand overnight with as much surface as possible exposed to air, (e.g., in a bucket or dishpan).  Do not use soft water.  It contains potentially toxic amounts of sodium.  Try to water your seedlings from the bottom.  This practice discourages excessive dampness that can cause dampening off disease.

Do not fertilize your seedlings until they have formed their true leaves.  I have found that diluted fish emulsion works very well.  Try one tablespoon per gallon of water.

Finally, try and maintain a humid environment for your seedlings.  Use plastic over the containers or place the plant in waterproof containers holding 1 inch of pebbles with ˝ inch of water.

Moving Your Plants Outdoors

Assuming you have prepared your garden site and are ready to plant out, it is important how you prepare your tender seedlings to enter the cold, hard world.

First, be sure that the last expected date of frost has passed in your area.  Then a week or so before that date, water less and do not fertilize your seedlings.

Young transplants are very sensitive to direct sunlight.  Begin with a few hours of filtered sun.  Gradually increase the amount of sunlight until, at the end of a week or ten days, the seedling is able to take a full day of sunlight.

Monitor your seedlings closely as they may need more watering.  At the end of this period, your little seedlings will be ready to grow and produce a bounty of vegetables for you, your family, and friends.  It is time to transplant them into your garden.

University of California Cooperative Extension Master Gardener Volunteers can provide additional gardening information upon request .Call the San Luis Obispo office at 781-5939 on Mondays and Thursdays from 1 to 5 PM.  You may also call the Paso Robles office at 237-3100 on Wednesdays from 9 AM to 12 PM.  The San Luis Obispo Master Gardeners website is at http://groups.ucanr.org/slomg/.  Questions can be e-mailed to: mgsanluisobispo@ucdavis.edu.