Seed Germination: Preparing for Spring

Ensuring appropriate temperature, moisture, light exposure, and planting depth are four critical factors for effective seed germination (image courtesy: www.epic.gardening.com).

By John Green, Certified Texas Expert Gardner, Orange County, TX

Happy New Year everyone! Winter seems to be fickle this season…a few cold days followed by an abundance of balmy days, followed by a chilly day or two- it’s confusing for plants and people. Several fruit trees on my property (pear and nectarine) which have decided spring has arrived and set bloom. This isn’t a problem until ‘real’ winter weather wanders into the area, at which point harvest will be negatively impacted. This is our SETX climate which is continually changing…people and plants must learn to adapt! 

Typically, my suggestion this time of year would be to make good use of cold and rainy days by reviewing seed and gardening catalogues, selecting seed varieties, then forming a list of flowers and vegetables to purchase, while ensuring cultivation space availability! This year a slight adjustment is needed since the current weather pattern is perfect for expanding garden areas, adding new flower and vegetable beds, repairing damaged beds, amending beds with supplemental nutrition such as composted manure, compost, or a fresh layer mulch. After spending the day working outdoors, then allocating evening hours to review catalogues has proven to be an efficient use of time, particularly as the frequency of colder days is diminishing. After reviewing a couple of 30-day weather forecasting sites, predictions suggest balmy conditions will remain with daytime temps ranging to the mid-70’s over the next month.  

Seed catalogues are filled with detailed, useful information, and provide gardeners an opportunity to learn about new plant varieties which can aid in determining if the plant 

variety is a good match for ‘specific’ growing conditions. Each Spring my preference is to germinate most of my vegetables and flowers from seed selected from catalogues. Seed selection 

and availability are exceptional (if ordered early), often surpassing local availability, and providing a significantly larger selection. I often purchase several varieties of tomatoes (mainly Polish & German varieties) and peppers which are not locally available. 

For tomato seeds, my all-time favorite seed catalogue is Totally Tomatoes. The catalogue has pepper and other vegetable seed varieties as well, but its primary focus is geared toward tomato growers. They literally have hundreds of tomato varieties from heirloom to amazing new hybrids, many of which are suited to our SETX growing environment. Once seed selections are decided, it is important to place orders quickly, since quantities are limited and seed vendors sell out fast. Rember time is needed to begin the germination process in preparation of spring planting.   

According to the Old Farmer’s Almanac, the last frost date for SETX is February 29^th, give or take a couple weeks due to our ever-changing weather patterns. If you decide to plant cold-sensitive vegetables early (speaking from years of experience, as I’m always pushing the envelope by planting early), gardeners must be prepared for a late frost and have materials on-hand to do so! To get an early start for spring planting, many gardeners (me included) start seeds indoors or in a greenhouse. Germinating seeds into plants is extremely economical. It’s easy to calculate when to start seeds for germination, use the anticipated last frost date and count backwards the number of weeks needed to transplant outdoors, generally 6 to 8 weeks.  

Some types of small pots are needed for seedlings to germinate, and upcycling old garden pots is always a good idea, while being environmentally sensible. If reusing a previous year’s germination tray or pots, sanitation is critical for successful seed germination. Thoroughly clean trays and pots by removing used soil. Place the trays and pots into clean, soapy, water and scrub them to remove soil clinging to the interior sides of the containers. Rinse the containers with clean water. Make a bleach sanitizing solution by mixing a ratio of 1:9 parts (bleach to water) and pouring into a clean 5-gallon bucket. Completely submerge the washed trays and pots, allowing them to remain in the solution for 5 minutes. Remove containers from the bleach solution and dry completely. Another option is to purchase new germination trays or pots which is less effort but creates waste.

Once the containers are sterilized, the containers are ready to be filled with a purchased seed soil mix which is inert. It’s best to use a soil mix specifically made to start seeds, since the soil mix must be very light having the ability to hold moisture, while permitting air flow into the soil. Mix the soil with several cups of water and mix thoroughly. Place a hand full of soil in your palm and squeeze tightly. If the soil forms a ‘loose’ ball and holds its shape, the correct amount of moisture has been added. If a ball doesn’t form, continue adding water and mixing, then squeezing into a ball until the desired moisture content is reached. Then fill each container with soil, lightly tapping the container to remove air pockets. The pots are ready for seeds to be planted.   

Seed packages provide detailed planting instructions with most stating to cover the seeds with at least ¼ inch of soil. Note: if following seed packet instructions, seeds will often not germinate 

properly or only a few seeds will sprout.  It is possible and highly likely the seeds should not be covered with soil. Many seeds need light to germinate so covering them with soil impedes germination. There are also many seeds which require darkness for germination.  The amount of light or dark grossly affects their germination as does temperature which should range between 60-70 ℉. Find a warm location, such as the top of a refrigerator or freezer, to provide bottom heat for the seeds’ container or consider purchasing a heating mat designed for seedlings. Keep the soil moist during germination, and always water containers from the bottom (soaking the container in slightly warm water). 

The following list is a few common vegetable and flower seeds with respective light and temperature requirements. If you are searching for a particular vegetable or flower not included below or need a more extensive list, visit the local Texas Master Gardeners’ association website: https://txmg.org/orange/seed-chart-veggies/, or visit Aggie horticulture website: www.aggie-horticulture.tamu.edu for a wider selection of plants, flowers, and vegetables. 

So long for now fellow gardeners, let’s go out and grow ourselves a greener, more sustainable world, one plant at a time! Please continue sending comments & questions: jongreene57@gmail.com.