Since spring is approaching, you might be considering what kinds of plants to grow in your vegetable garden, and whether to start from seeds or transplants. There are several reasons why gardeners choose to start their plants from seeds rather than transplants. Although starting from transplants may be more convenient, seeds have several advantages including more variety and control over your plants. Before you begin, it is helpful to utilize a planting schedule to help you organize and keep track of your plants.
1. Sort your Seed Packets
Often, seed packets will provide you with instructions on when to sow your seeds. Sort them based on their start dates and whether they should be direct-sown or planted indoors first. Some seeds are better started indoors, while others fare better if directly planted outside. Peas, beans, watermelons, carrots, and corn can be sown directly outside. Basil, lettuce, onions, and tomatoes can be started indoors.
2. Start your chart
You can start a calendar or set up a chart based on the information to better help you manage your seeds. To begin, find the average last frost date for your area, which refers to the average final spring frost for your location. There are many ways you can find the last frost date. An easy way is to calculate it by zip code. It is also helpful to know your hardiness zones and which plants are compatible in your zones.
3. Figure out the Dates
Calculate when to sow and transplant your plants based on the frost date and record it on the chart. Keep in mind that frost dates are based on historic temperatures and may not be entirely accurate. You should monitor temperature forecasts to ensure that you do not plant your seeds prematurely and expose them to damaging weather conditions.
4. Record the Dates
A basic spreadsheet consists of the name of the crop, the number of seedlings needed, the date sown, and the date transplanted. You should also record the actual dates of germination and transplanting for each seed type. This will allow you to improve your planting methods for next year and make adjustments if necessary.
Factors that Affect Start Date
There are many factors that affect the time of a seed’s germination rate, including the time of planting, the soil temperature, and environmental conditions. These include external factors such as adverse weather conditions and internal ones such as the quality of the seeds. Below are several factors that may affect the germination rate for your seeds.
Soil temperature: Soil temperature is a crucial factor in determining the start date of seeds. Most seeds germinate at temperatures between 70 – 80℉. If the soil temperature is too cold or too hot, they will not sprout, or not at all. To check your soil temperature, purchase a soil thermometer and place it in the soil. For accuracy, take the temperature in both the daytime and nighttime and average it.
Growing conditions: If planted in soils with subpar composition or unideal growing condition, the germination rate is greatly reduced. It is important that plant your seeds in areas with the appropriate soil type, moisture level, and amount of sunlight. Generally, most vegetables will grow in sandy loam, which is soil that is well-draining, loose, and rich in organic matter. Soils low in organic matter and containing heavy clays will hinder the development of an extensive root system, leading to stunted plant growth.
Heat: Most seeds require consistent warm temperatures to germinate. If you are growing your plants under a greenhouse or in a raised garden bed, then you can start your seeds earlier. In raised garden beds, the soil warms up faster, allowing you to plant earlier and extend the growing season. We recommend Vego Garden Beds for high quality, long-lasting performance.
When starting seeds indoors, consider using heat mats, which will increase the chance of germination. While they aren’t necessary, they provide a balanced, regulated heat source to your seed trays and assist in uniform germination. You can remove the heat mat once the seeds have germinated, as they should only be used to start seedlings.
Lighting: Supplemental lighting is recommended if you are starting seeds indoors, especially if you are growing plants that require long hours of direct sunlight. It aids in the germination process by improving crop production. Although there are fancy kits available, you can purchase cheaper fluorescent ones commonly used in basements and workshops. You can use T12 or T8, but T5 and LED grow lights are more efficient.
Seed Quality: You should choose local, organic seeds, as the plant is already suited to your growing environment and hardiness zone. Before planting, consult your seed packet or online catalogs for the optimal time to begin sowing, or whether it should be planted indoors or directly outside. Check the packet to make sure the seeds aren’t expired. If a seed is not viable, it will not germinate.
Tips to Consider Before you Start
Once you have gathered all your materials, you are ready to start planting. Below are several tips to consider to ensure a plentiful harvest.
- Start Seeds at the Right Time: For those starting seeds indoors, the standard time is 6 weeks before your final frost date. Some can be started 8 weeks earlier, or later, depending on the growing conditions and type of plant. Refer to your seed packet for specific planting dates and instructions.
- Start Seeds Indoors: To get a head start, many gardeners start their seeds indoors. Make sure that the container or tray you select has good drainage.
Use High Quality Seed-Starting Soil Mix: Seed starting mix should be sterile, light-weight, and moisture retaining while also well-draining. These mixes do not actually contain soil, and are instead composed of materials such as peat moss, perlite, compost, or limestone. Potting soil is not recommended, as it contains large debris that can inhibit the growth of plants and lacks nutrients. You can buy commercially available starting soil or make your own. A simple mixture of equal parts peat moss and vermiculite is common.
- Harden off your Seedlings: Before transplanting your seedlings outside, harden them off to gradually acclimate them to the outdoors and prevent transplant shock. Move your seedlings to a protected location for a few hours each day, starting with an hour for the first day and add an hour each day for one week. Do not place them in a windy location and avoid direct light. This process should take a little more than a week, until they can be left outside overnight as long as the temperatures do not drop below freezing. After your seedlings have hardened off, they are ready to be transplanted.
Spring Schedule of Seed Sowing
Below are the general sowing dates for common vegetables. The actual date will depend on your weather conditions, which you should observe to ensure optimal planting conditions.
- 5 – 7 weeks before last frost: leeks, onions, peas, dill, garlic, shallots
- 4 weeks before last frost: kale, cabbage, spinach, mustard
- 2 – 3 weeks before last frost: lettuce, turnip greens, parsley
- 1 – 2 weeks before last frost: beets, carrots, parsnips, radishes, broccoli, brussels sprouts, potatoes
- On or after last frost: beans, corns, squash, pumpkin, winter squash, summer squash, zucchini
- 1 – 2 weeks after last frost: Cucumber, lima beans, watermelons, tomatoes, peppers, peanuts