Even with recent chilly days, it’s time for gardeners to start preparing for summer vegetables, flowers and herbs. Seed planting is often scheduled by the date of the last spring frost. In Pittsburgh, the average last frost date is May 15th.
Different seeds require different start times. Temperature-sensitive crops like tomatoes should be started this week indoors. Consistent water and heating for 6 to 8 weeks will help tomato plants reach maturity before they are transplanted outside, according to Grow Pittsburgh's Garden Dreams Greenhouse and Farm Manager Hanna Mosca. She says tomatoes are a relatively easy crop and great to share with family and friends.
“There are just so many thousands of varieties of tomatoes, so you can grow so many unique and rare things that you might not be able to find at local nurseries or hardware stores,” Mosca said.
Other plants, like beets, broccoli, cabbage, and cauliflower, should be started 4 to 6 weeks before the last frost date.
While these plants should be started indoors, other plants like carrots, peas, arugula, and radishes can be directly sown, meaning they can be started outside. These crops are more resistant to the rapidly changing temperatures of southwestern Pennsylvania.
Once seeds receive proper conditions, they begin the process of germination. First, the seed coat swells and softens as the seed absorbs water. As the seed coat is ruptured, a primary root emerges. In the final stage of germination, a shoot starts growing upward as it breaks through the soil. Shortly before or after the last frost date, plants typically have a few leaves and are ready to be transplanted outside or into a pot.
Mosca recommends that beginner gardeners start by growing kale or collards. The seeds only take three or four days to germinate, and unlike pepper plants, they don’t require extra heat. Gardeners are able to harvest them well before they are in stock at local grocery stores.
Pittsburgh is located in USDA Hardiness Zone 6b. This map indicates which plants are best suited for certain areas. In 6b, a wide variety of produce can be grown. Artichokes, mustard greens, parsley, and fennel are a few options.
Seeds can be started in any “celled” vessel with holes in the bottom for drainage. Mosca says that yogurt containers and plastic cups are great options. Paper egg cartons work, too, but the seeds need to be transferred to larger containers sooner.
One of the most common mistakes she sees with home gardening is over-watering.
“They really do not want wet feet, just like we don't want to be standing in a pond,” Mosca says. “Seeds don't want to be swimming, so keeping it moist is good, but you don't want them to be drowning.”
Using a spray bottle or fabric pots can help ensure that plants aren’t being overwatered. It helps to set the containers on rubber mats or near a drain for easy cleanup.
Another common mistake is not having a powerful enough light source. Seeds grown by windows alone often turn out tall and skinny, and because the stocks reach for the light. Using an artificial overhead light helps plants to remain stocky, short and sturdy enough for transplant.
For seed germination, ideal temperatures typically range from 65 to 80 degrees. Some plants benefit from heat mats, and others just need a space heater nearby.
You don’t necessarily need a big backyard to have a garden this year.
“Containers are great, and you can do a variety of sizes. Even tomatoes and peppers can grow in a container. You just want something bigger, like the size of about a five-gallon bucket,” Mosca said, “Things like basil or dill or cilantro can be grown in much smaller containers. Even kale and collards absolutely could grow in a pot, so you could have a really beautiful, diverse garden just in containers.”
Plants in containers need more consistent watering because their roots can’t source groundwater.
