Zone 6a Planting Guide: A Month-by-Month Calendar for Success

Gardening by USDA Plant Hardiness Zone is indeed an excellent starting point, especially when determining what and when to plant. For those in Zone 6a, understanding the nuances of your specific climate is key to a thriving garden. This Planting Guide For Zone 6a combines general zone guidelines with practical advice, local expertise, and the importance of keeping annual garden records to create your personalized and effective gardening calendar.

January

January in Zone 6a is all about winter garden maintenance and preparing for the growing season ahead. Even in the cold, there are crucial steps to ensure your garden’s health and future productivity.

Regularly check trees and shrubs for ice and snow accumulation. Gently brush off heavy loads to prevent branches from breaking under the weight.
Apply tree wrap to the trunks of newly planted trees and thin-barked species like linden, ash, mountain ash, and maple to protect them from sunscald and frost cracks.
Revitalize your indoor houseplants by giving their leaves a thorough cleaning. Dust buildup can impede light penetration and hinder gas exchange. Use a soft cloth dampened with water and a mild, scent-free soap solution to wipe leaves clean.
Begin planning your garden layout for the upcoming season. Consider crop rotation strategies from the previous year and initiate any carpentry projects such as building cold frames, trellises, or setting up indoor grow lights.
Start the stratification process for perennial seeds that require cold treatment. This can be done by planting seeds outdoors or by simulating winter conditions in your refrigerator.
Review your gardening records from the past year, paying attention to planting dates, fertilization schedules, and pest control measures. Note successful plant varieties and those you wish to try again, and prepare your seed orders accordingly.
Inspect houseplants meticulously for any signs of insect infestations. Isolate any new holiday gift plants until you are certain they are pest-free to prevent infestations from spreading.
Incorporate garden record-keeping into your New Year’s resolutions by starting or updating your garden journal. Document the performance of different flower and vegetable varieties in your garden to inform future planting decisions.
If you haven’t already, order seed catalogs from reputable seed companies. Explore companies that specialize in open-pollinated and heirloom varieties for unique and resilient plants.
Pre-order bulbs and live plants for the entire year from your preferred suppliers to secure your desired varieties and avoid missing out when planting season arrives.

Alt text: Winter scene in Zone 6a garden, highlighting January gardening tasks like snow removal from trees.

February

February in Zone 6a marks the late winter period where anticipation for spring gardening grows. Focus on preparations to ensure you’re ready to maximize the coming growing season. Proactive planning now will pay dividends as the gardening season progresses.

March

March is the signal to get going in Zone 6a! Starting seeds on time is essential to take full advantage of the growing season. While it might seem like a lot to do at once, early efforts will result in a flourishing and productive garden.

If you haven’t already, prune your fruit trees, berry bushes, and other woody ornamentals early in March. Complete pruning while plants are still dormant, before the onset of spring growth.
Plant potatoes, strawberries, asparagus crowns, rhubarb, and onion starts this month as soil conditions allow.
Direct sow seeds outdoors for hardy annuals like Nigella, Poppy, and Delphinium. These seeds benefit from a period of cold temperatures to enhance germination.
As daylight hours increase, houseplants will resume active growth. Repot them if necessary and provide a balanced fertilizer to support new growth.
Start seeds indoors early in March for long-season vegetables like eggplant, peppers, and tomatoes to get a head start on the growing season.
Beat the spring rush by taking your lawnmower and other power tools for servicing now, ensuring they are ready when you need them.
On warmer days, turn your compost pile to aerate and speed up decomposition. Avoid working garden soil if it’s still too wet and cold to prevent soil compaction.
Clear any remaining dried plant debris from garden beds and add it to the compost pile to clean up garden spaces.
Fertilize grapes, raspberries, and blueberries before new growth begins to provide essential nutrients for fruit production.
Acquire a dedicated notebook to serve as your garden journal. Document planting details, including seed company names, plant varieties, planting dates, and harvest dates. Throughout the season, record plant performance, disease susceptibility, and treatments used. This information is invaluable for future garden planning.
Place birdhouses outdoors this month if you built them over the winter. Birds will soon be seeking nesting sites, and providing homes encourages beneficial wildlife in your garden.
Get your soil tested to determine nutrient levels and pH balance, allowing you to amend the soil appropriately before planting. Contact your local Extension Agency for soil testing resources and instructions.
Towards the end of March, remove winter protection from perennials and gently pull back mulch from strawberry and asparagus beds to facilitate spring growth. Side-dress asparagus with a gentle, natural nitrogen fertilizer to encourage vigorous spear production.

Alt text: Vibrant spring flowers blooming in Zone 6a garden in March, signifying the start of active gardening season.

April

While warmer weather in April in Zone 6a is encouraging, resist the urge to rush planting tender plants outdoors. Continue hardening off seedlings and focus on direct sowing cool-weather crops.

Begin hardening off transplants during the first week of April. Onions, parsley, and other cool-season crops that are at least 5 weeks old can start the hardening-off process. Choose smaller cole crop seedlings (broccoli, cauliflower, cabbage, Brussels sprouts) as overly mature plants exposed to early-season cold can bolt prematurely.
Install a rain gauge near your garden to monitor rainfall. Aim for approximately one inch of water per week from April through September to maintain optimal soil moisture.
Direct sow seeds outdoors for cool-season vegetables like asparagus, beets, carrots, Swiss chard, kohlrabi, leaf lettuce, mustard greens, parsnips, peas, radishes, spinach, and turnips.
Scatter annual flower seeds in flower borders. Fine seeds require no soil covering and will germinate quickly to provide early summer blooms.
Continue “hilling up” potatoes as shoots emerge to encourage tuber development and prevent greening.
Plan any new landscaping projects on paper first. Avoid overplanting and ensure you know the mature size of each plant, allowing ample space for growth.
Prune raspberry canes that will produce this year’s fruit by about ¼ of their length before growth resumes. Remove last year’s fruiting canes if you haven’t already done so after last season’s harvest.
By the second or third week of April, begin hardening off frost-tender plants, including vegetables, herbs, and annual and perennial flowers started indoors, to prepare them for transplanting outdoors.

May

May is a pivotal month in Zone 6a, typically marking the average last frost date. After this date, it is generally safe to transplant tender seedlings outdoors. However, always monitor local weather forecasts and recommendations, as last frost dates are estimates.

Continue starting seeds indoors for warm-season crops like okra, squash, cucumber, melons, and watermelons. Sow vining crops in individual peat pots to minimize root disturbance during transplanting.
Sow another round of seeds outdoors for beets, carrots, Swiss chard, kohlrabi, late cabbage, leaf lettuce, mustard greens, collards, turnips, radish, spinach, onion seeds for bunching onions, and peas for a continuous harvest.
Aim to plant any new trees and shrubs by the end of May to allow them to establish roots before the heat of summer.
Keep hilling up potatoes as they grow to maximize yields.
Install trellising systems for your tomato plants before they start sprawling to provide support and improve air circulation.
If the weather forecast is favorable, direct sow seeds outdoors for beans, okra, squash, sweet corn, and watermelon. Plant beans and sweet corn in partial rows for successive plantings every week or two. Plant sweet corn in paired rows or blocks for effective pollination.
By the end of May, it should be safe to plant almost all crops outdoors in Zone 6a. Houseplants can also be moved to a shaded location in the yard for their summer outdoors.
Plant sweet potato slips after the soil has warmed sufficiently, which may be late May or early June in Zone 6a.
Direct sow warm-season flowers and herbs like sunflowers, nasturtiums, marigolds, borage, basil, and other heat-loving varieties.

Alt text: Lush Zone 6a garden in May, showcasing diverse plantings and indicating peak planting season.

June

June in Zone 6a requires vigilance in seeding successions and pest management. Successional sowing extends your harvest, while early pest identification and control are crucial for a healthy garden.

Protect Brassica crops (cabbage family) with floating row covers to prevent damage from cabbage moths and flea beetles if these pests have been problematic in the past.
Monitor for Colorado potato beetle adults, eggs, and larvae. Hand-pick and remove them or use an organic insecticide if needed. Be aware of the yellow-and-black-striped adults, yellow eggs laid in clusters on leaf undersides, and red, humpbacked larvae.
Watch out for striped and spotted cucumber beetles, which can transmit bacterial wilt to squashes and melons. Hand-pick adults and eggs throughout the season.
Be vigilant for Mexican bean beetles. Consider using floating row covers as seedlings emerge to protect the crop.
Aphids can appear on various plants as temperatures warm. Check new foliage for infestations and sticky leaves (honeydew). Dislodge aphids with a strong jet of water or use insecticidal soap for control, repeating treatments as needed.
Squash vine borer moths emerge in early June. Inspect squash and summer squash stems daily for their brown, button-shaped eggs and remove them manually. Wrap stems with aluminum foil or floating row covers to deter egg-laying.
Early June is ideal for taking softwood cuttings of shrubs like spirea, lilac, and viburnum to propagate new plants.
Avoid working in the garden when plant leaves are wet to minimize the spread of diseases between plants.
Water vegetable gardens deeply once a week rather than light daily watering. Deep watering encourages deeper root systems, improving drought tolerance.
Monitor spring crops closely. Hot weather can cause lettuce to bolt and become bitter. Plant warm-season crops as soon as spring vegetables are harvested to maintain productivity.
Prevent blossom end rot on tomatoes, peppers, squash, and watermelons by maintaining consistent soil moisture through mulching and proper watering, planting in well-drained soil, and avoiding deep cultivation near plants. Calcium-rich fertilizers like bone meal can help correct blossom end rot. Avoid high-nitrogen fertilizers.
Continue seeding warm-season vegetables like beans, summer squash, and cucumbers for a continuous supply.
Weed the garden regularly to manage weeds effectively and prevent them from competing with your crops.

July

July in Zone 6a is harvest time! Stay on top of harvesting to prevent crops from rotting, becoming overgrown, or succumbing to pests. Continue succession planting, watering, and deadheading flowers.

Start seeds indoors now for heading cole crops for your fall garden. Direct sow radishes, carrots, beets, turnips, and kale in late July through August for fall harvests.
Monitor tomato plant leaves for signs of leaf spot diseases and take action if necessary.
Continue monitoring for pests as listed in the June task list and implement control measures as needed.
Deadhead garden flowers, both annuals and perennials, after blooming. Removing spent flower heads encourages further blooming or redirects energy to foliage and root development.
Fertilize flowering annual plants with a balanced fertilizer as they begin to bloom, as flowering is energy-intensive. Consider a second fertilization later in the season.
Continue sowing seeds throughout July for late crops of beets, bush beans, carrots, Swiss chard, cucumbers, and summer squash. Cover seeds with pre-moistened potting soil mix and a thin layer of mulch or floating row cover to retain moisture.
Divide and transplant bearded iris using vigorous rhizome sections. Discard old center portions and trim leaves back to about six inches.
Control mosquitoes by eliminating standing water sources around your property. Consider installing a bat house to attract natural mosquito predators.
Ensure your garden receives one inch of water per week, either from rain or irrigation. Water in the early morning to allow foliage to dry before evening, reducing fungal disease risk. Mulch plants to conserve moisture and improve yields.
Check soil moisture in container-grown vegetables and flowers daily, as they may require watering twice a day in hot weather.
Pinch flowers off herbs like basil, mint, and oregano to promote bushier growth and delay flowering, extending harvest.
Harvest onions and garlic as their tops dry and fall over. Braid garlic tops and hang in a cool, dry place. Cut onion tops back to one inch and dry bulbs thoroughly before storing. Use any damaged produce immediately.

Alt text: Freshly harvested beets in July in Zone 6a, representing summer harvest season.

August

August in Zone 6a is about maintaining momentum. Continue weeding, watering, deadheading, and pest control. Start clearing out finished crops to make space for fall plantings.

Sow peas in mid-to-late August for a fall crop in Zone 6a, taking advantage of cooler temperatures.
Continue regular inspections for pests and pest damage. Remove pests and treat affected plants as needed.
After the final raspberry harvest, prune out old fruiting canes, leaving only 3-4 young canes per foot of row to prepare for next year’s growth and prevent disease. Prune shoot tips in spring.
Avoid pruning trees and shrubs in late summer, as it can stimulate new growth that may not harden off sufficiently before winter. Delay pruning until late dormancy in early spring.
Order and plant spring-flowering bulbs now for next year’s early spring display. Plan for a variety of flowering times to extend the spring bloom season.
Sow seeds for late crops of leaf lettuce, mustard greens, Swiss chard, and spinach for fall harvests.
Continue deadheading flowers to encourage a final flush of blooms before the end of the season.
Perennial flowers and bulbs may begin to go dormant this month. Mark their locations with labels or create a garden map to remember where they are for spring.
Check moisture levels in hanging baskets and containers daily, as they can dry out quickly in late summer heat.
Harvest summer squash and zucchini every day or two to maintain plant productivity.
Remove old plants that have stopped producing to eliminate potential shelter for insects and disease organisms.
Control weeds before they go to seed to reduce weed pressure in subsequent years.
Sow seeds of biennials like hollyhock and foxglove for blooms next year.
Dig, divide, and move daylilies after they have finished blooming.
Harvest cantaloupe when the stem easily separates from the fruit with gentle pressure.
If using a fall cover crop, sow seeds in late August to improve soil health over winter.

September

September in Zone 6a is a transitional month. Start considering storage for harvested crops, planning end-of-season tasks, and preparing for an easier spring.

Leaf lettuce, Swiss chard, spinach, and radishes can still be planted for fall harvests in Zone 6a.
Continue pest inspections, especially for bean beetles, which can have a late-season resurgence.
Bring houseplants that summered outdoors back inside. Hose them down thoroughly to remove any insects before bringing them indoors. Monitor for insects in the soil and treat if necessary.
Prepare for winter mulching. Bulk mulch delivery is economical, or consider splitting a load with neighbors.
Divide and transplant fibrous-rooted perennials every 3-5 years, generally. Fall is the time to divide and transplant spring-flowering perennials, while spring is better for fall-flowering plants like chrysanthemums. Cut back tops, prepare planting sites with organic matter, and water well.
Harvest pumpkins, summer squashes, and gourds for storage before the first frost. Handle pumpkins carefully to avoid damaging the rind.
Continue harvesting cool-season vegetables like radishes, lettuce, cabbage, Swiss chard, spinach, broccoli, and other cole crops. Parsnips, peas, Brussels sprouts, and kale develop enhanced flavor after a frost.
Allow plants to complete their natural growth cycle. Avoid late-season fertilization or heavy pruning, which can delay dormancy and make plants vulnerable to early freezes.
Fall is an excellent time to improve garden soil. Incorporate manure, compost, and leaves to increase organic matter. Wood ashes provide phosphorus, potassium, and calcium and can be used as a top dressing.
Keep strawberry beds weed-free. Fall weeding makes spring weeding much easier.
Sow any fall cover crops by mid-September to allow them to establish before colder weather.

Alt text: Harvested pumpkins in a Zone 6a garden in September, signifying fall harvest preparations.

October

October in Zone 6a often marks the last major planting push. Plant garlic, shallots, and spring-flowering bulbs. You might even fit in a final planting of loose-leaf lettuce with season extension techniques. Monitor the weather, finish harvesting, store crops, and save seeds.

Plant garlic, shallots, walking onions, and potato onions for next season’s harvest.
Plant spring-flowering bulbs like tulips, daffodils, and hyacinths for spring color.
Drain hoses and empty bird baths before hard frosts to prevent damage from freezing.
Bury potted perennials in an empty garden bed or surround them with straw for winter protection.
Collect soil samples for testing to guide fertilization for lawns, vegetable gardens, shrub borders, and flower beds next year. Take separate samples for different areas and plant types.
Dig and divide spring and summer-flowering perennials now. Divide late summer and fall-flowering plants in spring. Cut back foliage, replant, and water well. Mulch after the ground freezes for winter protection in their first year after division.
Watch the weather forecast and harvest remaining summer produce like beans, eggplant, peppers, and tomatoes before a hard frost.
Cut and dry or freeze remaining herbs to preserve them for winter use.
Remove, chop, and compost asparagus tops after they have yellowed and died back. Mulch asparagus beds after the ground freezes.
Save seeds from favorite self-pollinating, non-hybrid flowers like marigolds. Allow flower heads to mature, dry seeds on newspaper, and store them in a cool, dry, dark place.
Note productive and unsatisfactory vegetable varieties from this year for next season’s garden planning.
Leave seed heads on asters, sunflowers, and cosmos for birds to feed on throughout the winter.

November

November in Zone 6a is a time for season extension and winterizing the garden. Explore season extension techniques for cold-tolerant greens.

Plant any remaining spring-flowering bulbs if you haven’t already.
Empty, clean, and store planters in a dry location for the winter to protect them from freeze-thaw damage.
Empty and turn over rain barrels to prevent freezing damage and disconnect downspouts to direct winter precipitation away from foundations.
Cole crops like Brussels sprouts, cabbage, broccoli, collards, and kale become sweeter after frost, so continue harvesting them. Use low tunnels to extend their harvest season.
Protect less hardy late-season crops like carrots, beets, leeks, rutabagas, turnips, winter radishes, Swiss chard, Chinese cabbage, and leaf lettuce by leaving them in the garden and mulching heavily with straw. Use floating row covers under straw for leaf lettuce to keep it clean.
Spread manure, sawdust, straw, and shredded leaves over the garden and till them in to improve soil fertility, structure, and water retention.
Continue monitoring houseplants for insects that may have been brought indoors and treat as needed.
Apply a 2-4 inch layer of protective mulch to garden beds after the soil has frozen to at least an inch thick to insulate plant roots.
Oil and store gas-powered equipment like lawnmowers and leaf blowers. Schedule tune-ups and blade sharpening now to avoid spring rush.
Order seed catalogs now for garden planning in January. Explore companies specializing in open-pollinated and heirloom varieties for unique selections.

Alt text: Bare tree in November in Zone 6a, symbolizing late fall garden cleanup and winter preparation.

December

December in Zone 6a is a time for reflection and planning. As the gardening year concludes, evaluate successes and failures, plan improvements, and consider new experiments for next season.

Consider gifting memberships to local botanical gardens, arboretums, or nature centers for holiday gifts, supporting these organizations while providing thoughtful and lasting experiences.
Protect trunks of young trees from winter damage by wrapping them. Protect multi-stemmed shrubs with chicken wire or hardware cloth to deter rabbits.
Clean garden tools with a wire brush and apply a light coat of oil to prevent rust. Sharpen hoes and spades. Clean and sharpen pruning tool blades. Sand handles and apply linseed oil or bright paint for visibility.
Drain fuel tanks of lawnmowers and tillers before winter storage.
Apply a layer of mulch to all planting beds, especially around perennials, if you haven’t already done so.
Protect root crops like parsnips, carrots, leeks, and beets with a thick straw mulch layer, allowing for harvesting into winter.
Avoid using rock salt (sodium chloride) for de-icing, which can harm plants. Use calcium chloride or potassium chloride products instead. For traction, use sand, kitty litter, or wood ashes sparingly. Minimize de-icing products to reduce environmental pollution.
Start reviewing and expanding your garden notes to refine plans for the next gardening year.

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