Garden Tips: Success in growing transplants

Do you plan on growing your own vegetable transplants from seed this year? The keys to success are ordering seed early, using the right potting mix, planting in clean containers, providing adequate light and sowing the seeds at the right time.

Now is a good time to buy seed for growing transplants or for planting directly in the garden. First, take time to carefully plan your garden and decide what types and varieties you want. If tight on space, seek varieties that are compact and recommended for containers or raised-bed gardening. Choose vegetables you like to eat and ones that are tastier when fresh picked, or pricier when bought fresh at the market.

I recommend using a quality potting mix when growing plants in containers, and this is especially important when growing transplants from seed. Look for a well-drained soil-less mix that contains peat moss or coconut coir fiber, perlite and vermiculite, and does not contain bark or compost.

Containers do not need to be fancy, just clean and with holes for good drainage. There are many seed-starting containers available from local nurseries and mail-order companies, but you can save money by recycling various plastic containers, such as yogurt cups or margarine containers. Before using re-purposed containers or recycled pots, thoroughly clean and sterilize them by soaking them for 15 minutes in a bleach solution (1 part bleach to 9 parts water). Finish by rinsing well and letting them dry.

Inadequate light is often the reason why gardeners fail when attempting to grow their own transplants. Once the plants germinate, they need lots of light. Even the light on a sunny windowsill is often not enough. Gardeners who are serious about starting transplants should provide supplemental lighting. The easy, but expensive route, is to buy a commercial plant stand with fluorescent lighting, but you can make your own with a two or four-tube fluorescent light fixture. To provide enough light, the bulbs should be kept 2 to 4 inches above the plants and raised as the plants grow. The lights should be kept on for 12 to 14 hours a day and turned off at night.

Germinating seeds and young plants need warmth, but not too much. Daytime temperatures should be between 60 and 80 degrees and nighttime temperatures between 55 and 75 degrees. Too little light or too warm temperatures will lead to weak and spindly growth.

A final factor in transplant-growing success is planting seeds at the right time. Frost sensitive warm-season plants, like tomatoes, will not be planted in the garden without protection until the danger of frost is past and the soil is warm. The average last date of frost for the Tri-Cities is in early May. Tomato seeds should be planted indoors about eight weeks before the last frost, peppers 10 weeks and eggplants 9 weeks. Squash, melons and cucumbers are also frost sensitive, warm-season plants, but they germinate and grow more quickly, and only need four weeks before planting them outdoors.

For more information on propagating plants from seed, go to http://bit.ly/plantsfromseed. For information on growing transplants at home, go to http://bit.ly/growing_transplant.

This story was originally published February 21, 2016 at 9:25 AM with the headline "Garden Tips: Success in growing transplants."