The Best Time to Plant a Garden in Maine

Cool Season Crops

• You can start planting cool season crops, such as peas (Pisum sativum), potatoes (Solanum tuberosum) and onions (Allium cepa var. cepa), in the spring as soon as you can work the soil. In Maine, that means as soon as mud season has passed and the soil has dried. This typically occurs in April or early May, depending on your location.

Warm Season Crops

• Warm season crops, such as tomatoes (Lycopersicon esculentum), cucumbers (Cucumis sativus) and peppers (Capsicum annuum), cannot be planted until after the last expected spring frost in the area. For northern areas, the last spring frost may not occur until well into June, depending on the year. Gardeners in southern locations may experience their last spring frost in early May.

Weather

• Weather conditions may interfere with planting, even if frost is not a danger. If weather remains cool and rainy in early spring, the seeds of cool season crops may rot in the soil or germinate poorly if you plant them. Although both potatoes and peas will germinate in soil at 40 degrees Fahrenheit, potatoes prefer soil that has warmed to 65 degrees F and peas prefer soil at 70 degrees. Those planted too early may take longer to germinate, while those planted a week or two later may catch up with them. Its not just the cool season crops that are affected by weather. Prolonged rainy spells in the beginning of June may make planting warm season crops difficult. Cool nighttime temperatures that dip below 50 to 55 degrees F, even after the danger of frost has passed, may stunt the growth of tomatoes and peppers.

Other Considerations

• The amount of snow the previous winter and the amount of rain received in the spring also affects the soil and how early it can be worked in your area of Maine. Sometimes, soil that is slightly moist can be tilled and allowed to dry, but this poses the risk of compacting the soil from working it when it is too wet.