When Can I Start Growing American Marigold Seeds In Massachusetts In A Greenhouse

When can I start growing American marigold seeds in Massachusetts in a greenhouse? This is a question that you must determine before sowing seeds, but the answer is as simple as marking your calendar eight weeks before the last frost. On the other hand, you can plant the seeds after the frost if you’re not using a greenhouse and want to cultivate it outdoors. 

But how does one determine the frost date of Massachusetts? Regardless of your state, every greenhouse grower must know the hardiness zone of their location. Massachusetts is in zones 5a to 7a, and you can use this to mark your calendar and determine the frost date.

When Can I Start Growing American Marigold Seeds In Massachusetts In A Greenhouse

American marigolds will thrive in Massachusetts since it is hardy for zones 3 to 11. These gorgeous flowers bloom in spring, summer, and fall, and are native to Mexico and Central America. They also go by the name African marigolds and Mexican marigolds, and you can distinguish them from being the tallest and most upright marigold. 


When Can I Start Growing American Marigold Seeds In Massachusetts In A Greenhouse: Calendar For Planting

You can start your marigold seeds indoors in Massachusetts before the last frost date. This can be eight weeks before or fifty days before. According to the University of Massachusetts Amherst, most areas in the state have their last frost date on May 15. 


Eight weeks before the last frost date

As mentioned previously, planting American marigold seeds in the greenhouse is best to do eight weeks before the last frost. Using the hardiness zone of your area in Massachusetts, you can determine this exact date. However, the time will be different if you are planting outdoors since it will be after frost and usually in spring. 

In general, the Massachusetts Master Gardener Association also recommends starting your seeds on the date counted away from the last frost date of your area. Marigolds are best to start indoors so you can get an earlier bloom. However, these plants have a short period from seeding to blooming anyway, and that’s why it’s possible to sow them after the danger of frost outdoors. 

Using the greenhouse is more strategic for gardeners, mainly because it allows you to safely start the flowers indoors. You can remember that the majority of areas in Massachusetts get their last frost at around May 15. Keeping this in mind, you can count back the number of weeks from when you want to transplant the marigolds into the greenhouse 


Fifty days before the last frost date

If you have started your marigolds around 50 days before the last frost date, this will prepare them well for mid-spring planting. Doing so, your plants will be at the right size without the need to worry about the challenges of the outdoor climate. You don’t even have to wait long for the seedlings to germinate.

Once this happens, remember to ensure that the plants get 6 hours of light per day. You can then thin the seedlings once you see the second set of leaves. Transplant them in their pot while waiting for the last frost date inside the greenhouse. 


Other Considerations For Growing American Marigold In A Greenhouse

After finding the answer to when I can start growing America marigold seeds in Massachusetts in a greenhouse, the success of your flowers will depend on other conditions. For example, seed germination will happen in as early as 4 to 14 days. However, this depends on the soil temperature, which should be between 70 to 75°F and indoor temperatures at 65 to 75°F.

Inside the greenhouse, you must use a warm and moist flower bed for sowing the seeds. After planting, you can expect the marigolds to bloom in 50 days until frost. Add organic matter to the soil and check the soil pH as it should be at 6.0 to 7.0. For the spacing, large varieties should be apart at 24 inches, 15 inches for medium types, and 6 inches for dwarf marigolds. 


What Makes American Marigolds Different From Other Marigolds?

Compared to other marigolds, you’ll notice that American ones are best planted in the spring. This is because they mature more slowly than French marigolds, for example. These tall flowers can act as planting pockets, or you can add them in front of shrubs to add some color in the garden. 

American marigolds will surely stand out as center or rear attraction in beds and borders. Some gardeners grow American marigolds to create a hedge around their herb garden as well. But what are the best varieties to cultivate? 

The popular ones include Antigua Series, Jubilee Series, and Vanilla. For hedges, Gold Coin Series American marigolds are excellent. 



Massachusetts is an excellent state for growing flowers. One of the common ones you’ll find are American marigolds, which can inspire you to question, “when can I start growing American marigold seeds in Massachusetts in a greenhouse?” You can plant the seeds before the last frost date, either eight weeks before or fifty days before. 

Knowing the hardiness zone of your area will help you determine the frost date accurately. While the last frost date in most areas in the state is on May 15, the hardiness zones in Massachusetts range from zone 5 to 7. Therefore, you must check your seasons to prevent drawbacks. 


Leave a Comment