Starting Garden Seeds - February 23, 2011
Jeff Schalau, Associate Agent, Agriculture & Natural Resources
University of Arizona Cooperative Extension, Yavapai County

Now is a good time to start warm season vegetable and flower seeds for transplanting into the garden. Tomato, pepper, and eggplant are somewhat slow and may take 10 to 12 weeks to produce a good transplant. These species are of particular interest because nurseries and garden centers often don’t carry the range of varieties people are interested in. Other plants such as beans and squash grow faster and transplants can be grown in as little as 4 weeks. I prefer sowing these directly into the ground. There are some simple guidelines for growing transplants. From there, you may need to invest in equipment or modify the methods to fit your budget.

Start with clean containers and sterile soil. New transplant containers can be purchased from horticultural suppliers. Old pony packs and other recycled containers can be reused and should be cleaned and sanitized in a 10% bleach solution to minimize “damping off” fungi and other diseases. Milk cartons, foam cups, and egg cartons make nice individual plant containers. Of course, these will need drainage holes poked in the bottom. Toilet paper, paper towel, and gift wrap tubes can also be used for containers if cut in two inch lengths and placed on end.

Sterile potting soil is available in bags from home and garden centers. Fifty percent vermiculite or perlite and fifty percent fine sphagnum peat, by volume, is excellent for starting seeds. A small dose of fertilizer (half of normal concentration) may also be added to homemade mixtures. Label them carefully and keep a garden journal listing your materials, planting dates, seed varieties, etc. so that you can continuously monitor progress and troubleshoot problems.

Fill containers with soil and moisten with water. Tamp slightly but don’t overly compact the soil media. Sow three seeds per cell by poking a hole and covering with soil mix. The rule of thumb is to sow seeds twice as deep as the seed size diameter. Gently water the containers without disturbing the seeds. This can be done by misting or allowing the water to soak in from below if the container type allows. Cover the soil surface with saran until the first signs of germination. Then remove the plastic cover immediately and be sure the container gets maximum exposure to light. A good temperature for germination is usually about 85 degrees F. Most seeds do not require light to germinate, but seedlings need full exposure to light as soon as they emerge.

Place the germinated seedlings in a bright window or artificial light to prevent soft, leggy growth. Simple artificial lights can be made by using a two tube fluorescent fixture that has one 40-watt cool white and one 40-watt warm white tube. Special grow light fixtures are also available. Plants should be kept six inches from the lights and lights kept on 16 hours per day. Raise the lights as plants grow. Temperatures of 55-60 degrees F at night and 65 to 70 degrees F in the day will prevent soft, leggy growth and minimize disease. Cold frames can also work well for starting plants, but monitor the temperature and watch for insects that may eat young tender plants.

As they develop, select the best seedling and thin them to one plant per cell/pot. Add water to soilless media only when moisture can no longer be squeezed out by pinching the medium between the thumb and forefinger. Water soil only when it no longer feels moist when rubbed between the fingers. Fertilizer should also be applied periodically. Liquid fertilizers are convenient for this purpose. Prepare the solution exactly as prescribed on the label. Transplant to the garden when roots fill the pots and white root hairs are visible on the sides of the root ball. You may want to use walls of water, hot caps, or another frost protection system if setting out before May.

Speaking of growing new seeds, our Verde Valley Satellite Office has moved from Verde Village to the Camp Verde Justice Complex at 2830 N. Commonwealth Drive, Suite 103, Camp Verde AZ 86322-8202. We also have new phone number: 928-554-8990. Our hours are M-Th 9 am to noon and 1-4 pm. Master Gardeners volunteers are also available to assist you (call ahead to ensure availability). It is a huge improvement for us and we thank the Yavapai County Board of Supervisors for making it possible!

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Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr. #C
Prescott, AZ 86305
(928) 445-6590
Last Updated: February 16, 2011
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