August 3, 2026, 11:17 am | Read time: 5 minutes
All summer long, zucchini grow rampant, and tomatoes produce fruit after fruit. This takes a toll on the soil. What remains after the season is exhausted earth. Some people automatically reach for a bag of fertilizer to rejuvenate the soil. But fertile soil needs more than just a few fertilizer pellets.
Whether in a vegetable bed or a container, tired soil is often depleted on two different levels, each requiring different solutions. myHOMEBOOK gardening expert Katharina Petzholdt explains how to make depleted soil fertile again.
What the Soil Lacks After Harvest
One issue is the nutrients that get used up over the season. Heavy-feeding vegetables like squash, cabbage, or tomatoes draw plenty of nutrients from the soil. The other issue is the soil’s structure, which changes more slowly over the years. If a bed is frequently walked on or worked when wet, it compacts over time, making it harder for water and roots to penetrate.
These deficiencies aren’t always visible in the soil. It can still appear dark and crumbly. The exhaustion is more evident in the plants, which grow weaker, produce less, or become more susceptible to diseases in depleted soil. Randomly adding a load of fertilizer might hit the mark or completely miss it.
The Benefits of a Soil Analysis
Random fertilizing rarely solves problems and can even create new ones. “Simply dumping fertilizer on the soil isn’t sensible because many garden soils are already oversupplied with potassium and phosphorus,” says horticultural technician Gottfried Röll from the Bavarian Garden Academy, which advises hobby gardeners through a garden hotline and online services.
Both nutrients are essential, but if they are too abundant, they can negatively affect plant growth and harm the environment.
Mineral fertilizers like Patentkali or lime are only useful where something is truly lacking. A soil analysis, which should be done every few years, is the best way to determine if there is a deficiency. It reveals what the soil needs and how to improve it specifically. In the intervening years, a routine of composting and mulching sustains the bed. A standard soil analysis with pH and main nutrients usually costs between 20 and 35 euros, while a more detailed one with humus content and soil type costs more.
Mulch Revitalizes Tired Beds
Compost is the remedy of choice for tired soil, whether in vegetable beds or under perennials and shrubs. It provides nutrients and feeds the soil life. These organisms break down organic material into nutrients that plants can absorb, loosen the soil, and keep it balanced. A layer of mulch made from grass clippings, leaves, straw, or shredded green waste works similarly. If the soil is heavy and clayey, incorporating some sand helps loosen the structure and introduce air. “Earthworms also create an airy structure with their tunnels. They love mulched beds,” says Röll.
Two habits further help the soil. Never leave it bare. Open soil dries out and becomes compacted in the rain, while a mulch cover protects it. And don’t dig up your beds. Turning the soil destroys the structure that has developed over months and disrupts the soil organisms that live in different layers. Gentle loosening with a digging fork is sufficient.
Also interesting: Is gardening without digging really more environmentally friendly?
Coffee Grounds & Co.: In Moderation, Not Inches Thick
Home remedies like coffee grounds, eggshells, or banana peels are said to improve the soil sustainably and easily. Gottfried Röll takes a pragmatic view. Such home remedies don’t generally cause harm, but the problem is often the dosage. “Home remedies are overrated, and often too much is used,” the expert says. “If coffee grounds are laid inches thick on the soil in a container, that’s obviously nonsensical.” It’s best to use home remedies like coffee grounds sparingly or add them to the compost, where they decompose and later enrich the beds when well mixed.
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Revitalizing Old Soil from Containers and Raised Beds
Different rules apply in containers because a pot or raised bed is a closed system. In open beds, the soil interacts with everything around it: soil organisms like earthworms or microorganisms migrate in, and roots explore new areas. A pot is cut off from this. The soil and life in containers, pots, or raised beds are all that is available to the plants growing in them.
To prepare old soil in containers or pots for the next season, remove the old soil and mix it anew: Mixing about one-third old soil, one-third fresh soil, and one-third compost creates a good foundation. Raised beds settle over the years as the coarse filling material inside decomposes. Every few years, they need to be emptied and layered with fresh material. In the intervening years, it’s enough to top up the upper layer with compost and fresh soil.
Green Manure Builds Up the Soil
The soil can be actively built up with green manure. Sown during a fallow period, plants like phacelia, clover, buckwheat, or lupine cover the soil, loosen it with their roots, and build humus; clover and lupine also collect nitrogen from the air. When worked into the soil or left as mulch, they return all this to the soil.
This is especially effective in vegetable beds, where beds become vacant between crops. In perennial beds or under trees, plants grow in the same place for years. These beds are given something back from above: a mulch cover and a handful of compost in the spring, year after year.