Seed Starting

With the end of winter in sight, many gardeners turn to one of the most exciting times of the year – seed starting! The catalogs have been coming in full force, and they all promise hundreds of beautiful and interesting plants. As you prepare to purchase and grow your own seed for the upcoming year, here are some things to keep in mind.

Timing is everything. Do a little research and set up a schedule for starting all your plants. Most folks will want all their young plants to be ready to go outside by the frost free date, which for us in Central Iowa is typically just before Mother’s Day. As with most things in nature, there are some exceptions to that rule. The cool season crops like lettuce, pansies, or beets can be put outdoors earlier in the year. At Reiman Gardens we will put out our cool season annuals, weather dependent, in early April. Use a spreadsheet or calendar to count back the weeks from the day you want your plants outside using the information on the seed packet. Many annuals will take six to eight weeks to germinate and get large enough to put outside, but some are as little as four and some are as long as twelve or sixteen. This is why a calendar is so helpful.

Once you have your schedule you can start planting. Use a well-drained seed starting mix and be sure it is moist, but not wet. Wet conditions can lead to a fatal problem with damping off which kills newly sprouted seedlings. Temperatures should be on the warm side and the addition of a heat mat to warm the soil can greatly increase success with germinating and growing new seedlings. These water proof seedling heat mats are readily available from most places that sell garden supplies and are placed under the flat or container to keep the soil warm.

Light is an important factor. Starting seedlings on the window sill can be difficult because you will often have seedlings stretching and bending towards the light even with diligent rotation of the container. An ideal situation includes artificial light supplied by a simple two or four foot, fluorescent, plug-in shop light on a timer. Be sure to hang it on an adjustable chain so the light is always no more than six inches from the top of the seedlings. Move the light as the plants grow. The goal is to have short stocky plants which will transplant outside with much greater success. Keeping the light source close reduces the seedlings stretching and helps achieve that goal.

We have already begun starting seeds for the early spring here at Reiman Gardens. Staff and volunteers will spend the next 10 to 12 weeks sowing, transplanting, and growing from seed over 200 different types of annuals for 2013. Spring has literally already sprouted in the greenhouses here!

Prepared by Aaron Steil, Manager of Public Programs