Manure and compost offer a practical way to boost soil fertility.

A simple, honest question many folks in Maryland soil love to ask: what kind of organic waste actually improves soil fertility? If you’re weighing the options, the straightforward answer is clear: manure and compost. They’re the duo that packs the most proven punch for healthier soil, better structure, and richer biology down in the root zone.

Let me explain by walking through the common contenders and why the two together tend to win.

First, what are the other options good for?

• Plastic waste (A): It’s a hard no for soil fertility. Plastic can break down into tiny bits and contaminate soil and water. It doesn’t supply nutrients, and it stubbornly sticks around too long. If you’re thinking about soil health, plastic is a distraction, not a fertilizer.

• Grass clippings and leaves (D): These are helpful, but mostly as building blocks for compost or as mulch. When they’re used alone, they don’t deliver the steady, balanced nutrient supply plants crave. They shine when they’re part of a composting system or layered into soil as mulch to conserve moisture and feed soil life.

• Food scraps only (C): Food scraps are a good feedstock for compost, but they aren’t a complete strategy by themselves. They’re part of the bigger compost picture—along with yard waste, manure, and other organic materials. If you treat them as the sole source of fertility, you’ll miss the longer-term benefits of a well-rounded compost mix.

Why manure and compost stand out

Manure and compost aren’t just about feeding plants in a one-shot way. They contribute to soil health in multiple, durable ways:

• Nutrients that stay around long enough to help crops

Manure is naturally rich in key nutrients like nitrogen (N), phosphorus (P), and potassium (K), along with trace elements that support plant growth. Compost brings a slower, steadier release of those nutrients as it breaks down. That steady drip-feed is kinder to roots and less prone to leaching than a quick jolt of synthetic fertilizer.

• Organic matter that builds soil structure

Both manure and compost boost soil organic matter. That matters because organic matter acts like a sponge: it helps soil hold water during dry spells and improves air flow when conditions are damp. With better soil structure, roots explore more easily and plants establish faster.

• A bustling soil ecosystem

Healthy soil isn’t just about nutrients; it’s about life. Compost and manure foster microbial communities, earthworms, and other beneficial critters. They break down residue, release nutrients, and keep the soil ecosystem buzzing. In Maryland, where we can see a mix of clay and loam soils, that microbial activity can be a game-changer for drainage, aeration, and nutrient cycling.

• A more resilient landscape

Soils rich in organic matter tend to resist compaction, hold water more effectively, and withstand weather swings better. That resilience is especially valuable in regions where storms and heavy rainfall can disrupt nutrient balance and soil structure.

How compost enriches soil (the middleman you don’t want to ignore)

Compost is a standout because it’s a carefully managed decomposition process. It’s not just “garbage turned into soil”—it’s a stabilization of nutrients and a gradual delivery system for soil life.

• Feedstock diversity matters

A good batch of compost comes from a mix: fruit and vegetable scraps, coffee grounds, garden clippings, shredded leaves, and even some manure if it’s properly composted. Each component adds different micronutrients and helps balance the carbon-to-nitrogen ratio that microbes love.

• Stabilization is key

Fresh organic materials can burn plants with sudden nutrient pulses or introduce pathogens. Proper composting cools those risks by stabilizing the nutrients and killing off many seed-bank organisms that you don’t want in your bed. The result is a humus-rich, crumbly material that’s easy for roots to penetrate.

• Time earns trust

Compost isn’t a miracle overnight. It takes patience and the right conditions—air, moisture, and turning to keep things aerated. When done well, you get a product that improves soil texture, boosts moisture retention, and provides nutrients in a form plants can use gradually.

Where grass clippings and leaves fit in

Grass clippings and leaves aren’t idle byproducts; they’re valuable inputs when managed thoughtfully.

• They feed the compost pile

Layered with other greens and browns, these materials speed up composting, add carbon and nitrogen in the right mix, and enrich the finished product with additional micro-nutrients.

• They contribute to mulch

When spread as mulch, grass clippings and leaves help reduce evaporation, suppress weeds, and slowly add organic matter as they break down. The effect on soil temperature and moisture balance can be noticeable, especially in spring and fall.

A Maryland angle: management and protection

Maryland has unique soil types and rainfall patterns, so applying organic waste wisely matters. The state supports nutrient stewardship through programs that guide farmers and landowners in how to manage organic amendments responsibly. A steady, informed approach helps protect waterways, prevent nutrient runoff, and improve soil health at the same time.

• Do-not-overdo rule

With manure and compost, more isn’t always better. The goal is to match what your soil can hold and what your crops need. Soil tests help determine how much organic matter to add and how often. In Maryland, soil testing is a common first step in shaping a sound soil-building plan.

• Right timing and placement

Incorporating compost into the soil rather than leaving it on the surface improves nutrient uptake and minimizes nutrient loss. Manure, when used, should follow guidelines that reduce runoff risk and protect water quality. If you’re applying near streams or during heavy rains, you’ll want to rethink timing and location.

• Keep an eye on phosphorus

Maryland’s nutrient management guidance emphasizes phosphorus in some soils and situations. Compost and well-managed manure can help balance soil P levels, but excessive application can lead to unwanted concentration in the soil and potential runoff. The goal is to build a long-term balance rather than a quick fix.

Practical tips you can use (without the guesswork)

• Start with a soil test

Knowing your baseline helps you tailor additions to what your soil really needs. It’s a practical step toward smarter fertility, not a guess.

• Build a diverse compost pile

Mix greens (kitchen scraps, fresh yard waste) with browns (dead leaves, shredded paper) and, if you have access to it, a modest amount of well-composted manure. The variety makes a richer finished product.

• Keep compost turning and moist

Think of compost like a living thing: it needs air and moisture to stay active. If your pile dries out, it slows. If it’s too wet, it can become compacted and smelly. Aim for a damp, crumbly texture.

• Apply evenly and incorporate

Spread compost evenly over beds and lightly mix it into the top few inches of soil. This helps roots access the nutrients and reduces surface runoff.

• Don’t overdo it

Even good materials can cause trouble if applied in excess. Follow soil test guidance and local nutrient management recommendations to avoid concentrating nutrients where they aren’t needed.

• Use compost as mulch too

A layer of compost as mulch in the garden can reduce moisture loss, suppress weeds, and feed soil life as it slowly breaks down.

A few practical caveats

• Not every situation is the same

Some soils respond beautifully to compost alone; others benefit from a measured amount of manure for a nitrogen boost. The best plan accounts for soil type, crop type, and rainfall patterns.

• Watch for odors and pests

If composting becomes smelly or attracts pests, you probably need to adjust moisture, aeration, or mixing, not abandon the idea.

• Keep it legal and safe

If you’re in a managed landscape or agricultural setting, follow local guidelines for manure application, storage, and timing. It’s not just about what grows well—it’s about protecting waterways and soil health for years to come.

The big picture: soil health, water quality, and a balanced approach

When you pair manure with well-made compost, you’re not just feeding plants. You’re feeding soil life, improving structure, and boosting the soil’s capacity to hold onto water and nutrients. In Maryland, where soils range from sandy to clayey and rainfall can swing, that balance matters a lot. It’s about building resilience: fewer nutrient losses, steadier crop performance, and a landscape that stays productive through changing seasons.

If you’re exploring soil fertility in a Maryland context, you’ll notice a common thread: organic waste, when managed thoughtfully, supports a healthier soil ecosystem. It’s less about a single fix and more about a steady routine of testing, adding amendments in measured amounts, and watching the soil respond. The result isn’t flashy, but it’s sturdy and real—the kind of soil you can rely on for summers, harvests, and the quiet work of roots pushing through the darkness.

A closing thought to take with you

Think of compost as the soil’s pantry: a place where nutrients, microbes, and moisture mingle so roots can feed and grow. Think of manure as the nutrient-rich backbone that gives a lift when soil needs it most. Put them together with care, and you’re not just improving fertility for a season—you’re investing in soil health that pays dividends for years to come.

If you’re curious to explore further, look into how soil testing, compost quality, and proper manure management intersect with Maryland’s nutrient stewardship guidelines. The more you know, the more confident you’ll feel about making soil-friendly decisions that support healthy plants and clean waters. And that’s a win for your garden, your students, and the land you call home.