March signals the true beginning of the gardening season in Arkansas, marking the transition from winter dormancy to vibrant spring activity. This month offers a unique window for gardeners to initiate planting efforts, balancing the lingering threat of cold weather with the rapidly approaching warmth. Gardeners must act decisively in March to take advantage of the cool, moist conditions that benefit early crops and to get a head start on those requiring a long growing season.
Understanding Arkansas’s Varied Planting Zones
Arkansas features a diverse climate, encompassing USDA Plant Hardiness Zones 7a through 8b. This variation means planting schedules differ significantly across the state. Northern Arkansas, particularly the Ozark regions, experiences cooler temperatures and later frost dates compared to the southern counties and the Delta region. The “Last Frost Date” is the most important factor for planning March planting.
In Southern Arkansas, the average last frost date often falls in March, allowing for earlier outdoor planting. Conversely, Northern Arkansas’s last frost date can extend well into April. Gardeners must check the specific average frost date for their county to make accurate planting decisions. Planting tender crops before this date risks losing them to unexpected temperature drops.
Cool Season Vegetables for Direct Sowing Outdoors
March is the prime time for direct sowing cool-season vegetables that thrive in moderate spring temperatures and tolerate light frost. These hardy crops benefit from being planted in the cool, moist soil before the intense summer heat arrives. Before sowing, work the soil only when it is dry enough to prevent compaction.
Root vegetables and leafy greens are excellent candidates for March direct sowing:
- Radishes, carrots, and turnips can be planted directly into the garden bed. Radishes germinate quickly, offering a harvest in about four weeks. Carrots and turnips require loose, deep soil and should be thinned promptly.
- Leafy greens, including spinach, kale, Swiss chard, and leaf lettuces, should be planted. Use succession planting by sowing a new batch every two to three weeks to maintain a continuous harvest.
- Alliums, such as onion sets and shallots, should be planted now, ensuring the base is seated firmly just below the soil surface.
- English peas are perfectly suited for March planting and should be sown an inch deep, often requiring a trellis or support system.
- Seed potatoes can be planted early in March, buried several inches deep in the prepared soil.
Warm Season Crops to Start Indoors
Warm-season crops are sensitive to frost and require a long growing period. They must be started indoors in March to ensure they are ready for transplanting after the final frost, allowing them to mature and produce before fall. Starting seeds indoors requires providing consistent light, warmth, and humidity.
Tomatoes, peppers, and eggplants should be started from seed indoors during mid to late March. These varieties need eight to ten weeks of indoor growth before they can be moved outdoors, typically in late April or May. Using a heat mat beneath the seed trays improves germination. Seedlings also require strong light, often provided by grow lights, to prevent them from becoming weak and leggy.
Long-season herbs like basil and rosemary also benefit from an indoor start in March. Basil is a tender annual that only thrives outdoors once all danger of frost has passed and night temperatures are consistently warm. Rosemary can be slow to start from seed and benefits greatly from the controlled indoor environment. Starting these indoors ensures a robust plant is ready for the garden once the soil and air have warmed.
Early Spring Flowers and Herbs
March is ideal for introducing early color and flavor with cool-season flowers and hardy herbs that withstand variable spring temperatures. These plants provide immediate visual interest while waiting for warm-season crops to be transplanted. Cool-season annuals fill beds and containers with color that lasts until the summer heat arrives.
Several resilient plants can be planted outdoors in March:
- Pansies, snapdragons, and dianthus are annuals that tolerate a light freeze and provide early spring blooms.
- Hardy perennial herbs like parsley and cilantro can be planted directly. Cilantro prefers cooler spring weather and will quickly go to seed once temperatures rise.
- Spring-planted bulbs, such as gladiolus and lilies, can be put into the ground in March to provide blooms later in the season.
- Planting dormant, bare-root roses is also ideal in March, allowing the roots time to establish before the active growing cycle begins.