November is the prime time to set up our soils for improvement over the winter. While the garden rests, work continues beneath the surface. A few broad steps now help support microbes for healthy roots and nutrient uptake for leafy upper growth.

Measures to improve soil in November also protect overwintering insects, including pollinators, for a balanced garden system year-round.

Laying the groundwork in the fall supports plant health in seasons to come. It builds soil, year after year, to improve structure. Clay and sandy compositions improve over time with action now. Applying garden amendments to improve soil in November is the basis for strong specimens with far-reaching roots in spring, able to withstand variable conditions.

What is Loam Soil?

Loams are ideal soil compositions for many of our favorite garden specimens. A balanced blend of silt, sandand clay particlesthey represent the optimal loose and airy soil structure.

Loams allow roots to penetrate as they grow to reach deeper moisture. More extensive roots mean increased resiliency against fluctuating seasonal conditions, from water levels to temperatures to wind resistance.

Loam soils are well-draining while retaining moisture. The largest sand particles allow good drainage. Clay, the smallest particles, pack down and slow water as it runs. Silt is a medium-sized particle with properties between clay and sand. With relatively equal parts of all three, the soil composition supports healthy root development.

Heavily compacted soils high in clay, or lean, sandy, or rocky compositions, are garden woes. They impact drainage and irrigationeither holding water like a bowl (clay) or whisking it away (sand). They make it difficult for roots to develop and to access essential nutrients and oxygen.

Soils high in organic matter, on the other hand, provide food for soil microbes and aerate as they decompose. The organisms convert the organic material (compost, manure, leaves, etc.) into plant nutrition. They also improve soil structure and lessen compaction as they break down the material.

Do a Soil Test

If you haven’t done a soil test in the last five years, it’s a good idea to complete one now. A November soil testwhether from your local University extension office or an at-home kitmakes the process easy.

If you want to know the specific nutrient levels of a specific garden bed or area, take samples solely from that zone. For a broader site analysis, dig the small soil samples from different areas of the site and combine them for a reading.

The soil test should include lab-interpreted results to provide recommendations for specific amendments to improve nutrient levels. The results also include the type of soil you’re working with and the amount of the amendment needed for improvement.

Topdress with Compost

Compost, timed right and in moderation, is the key to building rich, loam soil in November. Topdressing with a hearty one to two-inch layer this month insulates roots and regulates soil temperatures to support microbes against frozen conditions.

Soil microbes often burrow deeper into the soil and naturally become less active in cold weather. Compost in the fall also protects against soil compaction and heaving from winter conditions, and preserves aeration for roots.

By topdressing soil with compost in November, we’re giving time for the nutrients to incorporate and build in the soil over the months ahead of spring’s resurgence and planting. Use completely broken down organic matter, or sidedress with manure post-frost, as it won’t burn plants as it slowly breaks down and mellows.

Clay, compacted, or poorly draining soils are a challenge without the addition of compost or other amendments. Leaves may yellow, wilt, and droop as roots sit in water, unable to uptake moisture or nutrients to support the upper growth. They also lack access to oxygen in poor soils with standing water. Heavy soils like clay and lean ones like sand improve with amendments. It may take several years for degraded types, but building seasonally brings benefits over time.

Adjust pH

Soil pH is a significant part of the plant-soil relationship, and the proper pH makes all the difference in nutrient absorption. Soil texture affects pH, with sand, clay, and silt particles impacting how minerals like sulfur and lime infiltrate the soil.

A soil test will indicate pH levels, whether acidic (low pH), neutral, or alkaline (high pH). Most ornamentals and edibles grow best in slightly acidic to neutral soils, with a pH between 6.0 and 7.0.

A balance of soil texture and nutrients achieves the sweet spot, and amending in fall allows absorption before the active growing season. Knowing our pH levels also lets us select the best species for our landscapes. Some plants grow well in either acidic or alkaline conditions, depending on their native range and soils.

Soil pH levels that are too high or too low block nutrient availability to the roots. Leaves may become chlorotic due to iron deficiency and the inability to absorb necessary elements.

Acidic soils have a low pH that is raised by adding garden lime. Alkaline soils moderate with the addition of garden sulfur. Amend soil in November when soils aren’t frozen to maximize microbial activity.

Add Winter Mulch

Mulch provides valuable services toward winter protection of roots and soil health, too. A two to three-inch layer of bark chips, leaves, or clean straw protects against seasonal extremes like frost heaving, rapid temperature fluctuations, and dry conditions.

Mulch provides insulation, retains moistureand enriches nutrition for microorganisms in the soil as it breaks down. Wait until after a heavy frost to add extra mulch as plants are dormant.

Fall leaves are an easy resource for ready mulch with lasting benefits. They insulate roots, nourish soils as they decompose, and promote biodiversity as habitat for beneficial insects and other creatures that use them to nest, lay eggs, and overwinter.

To make a leaf mulchplace them as a natural cover across beds and bare areas. Leave them where they drop or lightly rake whole leaves into beds. Keep the leaf layer off of stems and trunks to prevent fungal problems. You can also shred the leaves with a mower before applying.

If you have excess leaves, store them in piles or towers to make leaf moldor add them to the compost pile as brown material. As the piles break down in about six months, they become a prime November soil conditioner and topdress material.

Plant a Cover Crop

If you plan on leaving beds empty this season, consider a cover crop to increase diversity, improve soilsand attract beneficial insects. Fall-planted grasses and legumes work with microorganisms to protect and enrich soils between primary crop-growing phases. They also work in raised beds for soil improvement when empty for the season.

Cover crops can be a nitrogen-fixing legumelike clover, beans, peas, and vetchto reduce or eliminate the need for fertilizer. Grasses like annual rye, oats, winter wheat, and buckwheat are cold-hardy and grow quickly for full coverage in erosion control, weed suppression, and nutrient cycling.

Cover crops can lead to rich loams by providing resources for microorganisms, nutrient cycling, and nitrogen fixation. As added organic matter, they break down for extra enrichment. Cover crop roots create channels to help with aeration and improve soil structure. They retain moisture and prevent excess drying.

Cover crops also reduce erosion, slowing runoff and absorbing water to keep soils from washing, especially in sloped sites. Leafy growth protects the surface against harsh winter conditions like winds.

Warm and Cold Climate Sowing

In warmer areas, sowing cover crops in November is prime for soil improvement. Cut them back after flowering and before they go to seed to prevent them from spreading and becoming weedy. Leave the cut material in place to become organic matter for the soil. Use them as mulch or turn them into the soil at planting.