Wednesday, February 3, 2010

Seed Starting

The end of January marks the beginning of tomato season for me - That's when I start my tomato and basil plants from seed. Seed starting is more difficult than buying plants and transplanting but it has some great benefits.

Benefits. First, you are in command of the plant from the beginning which means no chemical fertilizers to artificially speed the growth process (and thereby growing a weak plant susceptible to disease later on). You only use the chemicals you need. You have many more variety options than what will be available in the nursery, especially with heirloom varieties. You also dictate the timing and are not dependent upon what is available at the nursery.

When to Start Seedlings. It takes about six weeks from planting seed to transplanting plant for tomatoes. So here in the Hill Country, last freeze date is around mid-April so to plant April 15th, you would start your seedlings March 1st.

Early Start Tip. Generally speaking planting earlier doesn't buy you much in the way of and early crop because tomatoes are smart enough to understand daylight and ambient and soil temperature (even if we aren't). But I have a little trick that seems to give me a jump start, especially with heirloom varieties. I start a whole month earlier and periodically pot up my plants in successively bigger containers. This grows plants that are extremely sturdy and more ready to tolerate transplanting into the elements. The downside is the need to lots of room in either a greenhouse of very bright sunroom.

The Soil. Any good commercial seed starter mix will work. The "experts" will tell you that you need a sterile soil mix but I have used a home-made organic mix full of living microorganisms with good success - 90%+ germination. In my view, a sterile environment is a vacuum inviting pathogenic opportunists to come in and disrupt the health of my soil and plants.

My Soil Starter Mix Recipe. My recipe has varied over time but here is the general formula:
  • 1 part peat moss (claims to help prevent damping off disease)
  • 1 part vermiculite
  • 1 part horse manure (dried; not green)
  • 1/2 part greensand
  • 1/2 part sand
If you don't have any horse manure, use cotton burr compost or organic potting soil such as Garden-Ville. Mix thoroughly and remove and large pieces or screen using a 1/2 inch mesh.

Planting Containers. There are lots of choices here. Seedlings need very little space for the first two weeks. A square inch pot will work just fine. When starting a lot of plants, the smaller the better is usually the rule due to space and lighting requirements. But if you are just doing a few pots and are planning on keeping them in the pot for awhile, you can start with a 4 inch pot or even a plastic drinking cup.

My Favorite "Guaranteed" Planting System. Garden Supply sells a planting system called Propamatic which comes in several sizes. It is a complete propagation system with clear plastic dome, 40 cell planting tray, and bottom watering wicking reservoir. It is the secret to my success. I've tried other systems that look better and this one, for whatever reason, out performs the others. Check it out at www.gardensupply.com.

Lighting. You can start seeds in bright windows or in a greenhouse but I've had the best success with artificial lighting. I give my plants 16 hours a day of intense light. I start my lights on top of the boxes and actually let the plants grow around the light tubes. If you mount the lights too far from the plants, they will get leggy. Once the plants grow into the top of the light fixture, adjust the light height a few inches so that they are just above the top of the plants.

Choosing Lighting. While I'm sure that grow lights are great, I'm too cheap to buy one and I have had good success with regular fluorescent shop lights - the cheaper the better. I hang two two-bulb, four foot, light kits on each shelf which provides light for four 40-cell propagation kits.

My Shelf System. I have a three shelf unit with four light tubes on each shelf that can grow 480 plants at one time. I built it from 2x4's and welded wire which cost around $75 including the lights and timer. Not as pretty but much cheaper than the professional grower systems which cost $300 or more.

Heat. A final consideration is heat. I don't know exactly the temperature for starting tomato seeds (I guess I'm an amateur) but the soil must be at least around 60 degrees. The lights will produce some heat but if you choose to start your seeds in an unheated area such as a garage, be sure provide some heat. I started my seeds for years in a small garage storage room and used a cheap heater with a thermostat to keep the minimum temperature. The temperature needs to be constant at the beginning but it can vary more later. However, cold days will slow the growth process and affect the six-week cycle. Be sure to keep a thermometer under the lights to monitor temperature.

Planting. This is the easy part. Fill you pot with moist soil (water first if dry) and pack gently (too loose and water will not wick, too tight and the roots will struggle and delay growth). Plant seeds around a quarter inch deep. I usually plant a couple of seeds in each tray so I'm guaranteed a plant in each pot. Cover with soil. Some people will cover with peat moss to prevent damping off and other fungal diseases (see below).

Watering. Always water from below. In my opinion, this is the best prevention for disease. If you don't have an automatic wicking system, fill a leak-proof tray with an inch of water and set your pots in the water for 10 minutes. I always water seedlings with rain water. I water with pure water until the first mature leaves show up and then I mix 1 tablespoon of liquid fertilizer and 1 tablespoon of molasses with a gallon of water to water the plants. Allow the soil surface to stay as dry as possible but don't let the plants dry out even once!

Damping Off Disease. The biggest disease problem for seed starting is damping off disease - a fungal disease that causes the base of the new plant to shrivel and many times kills the plant. Convention growers treat the soil with fungicide. From an organic standpoint, there are things you can do as well. Top the soil off with peat moss which has natural fungicidal tendencies. Malcolm Beck recommends sprinkling corn meal (another natural fungicide) on top of the soil after planting. I think that good practices are the most important aspect of disease prevention. Watering from the bottom and keeping the soil surface dry seems to help. I use a small fan to keep the air from getting stale. I also use a custom homeopathic fungicide that I make to help prevent damping off.

Six Weeks and You Have Transplants! That's it - good soil, light water and heat and in six weeks, you will have your own tomato plants ready to plant! There is a lot of art to starting your own seeds so you may want to start small and go bigger as you gain confidence.



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