Improve garden soil: The basis for your garden and pool planning 2026
What makes garden soil fertile? Healthy soil stores 20-40 liters of water per square meter, contains 3-5% humus and is home to 100-300 earthworms per square meter. If you are planning your garden design or pool installation for 2026 now in winter, you should think about soil quality right from the start. With proven methods, you can improve your soil quality sustainably and save up to 200 euros a year on water and fertilizer costs.
What makes healthy garden soil
Fertile garden soil is a living system characterized by a crumbly structure with balanced proportions of minerals, air, water and organic matter. The ideal composition consists of around 45 percent mineral components, 25 percent each of air and water and 5 percent humus. This balance enables optimum plant growth and makes the garden resistant to extreme weather conditions.
A pH value between 6.0 and 7.0 is considered optimal for most garden plants, although specific plant groups may have different preferences. The water storage capacity of 20 to 40 liters per square meter is a decisive advantage, especially during dry periods. The dark color and pleasant earthy smell indicate a high humus content and active soil life.
Winter time is planning time for 2026
While nature is at rest, you now have the perfect opportunity to concretize your garden dreams for 2026. Professional garden designers take more time for in-depth consultations during the quiet season, and you can think through all the details without any time pressure. Early planning pays off, especially for larger projects such as a complete redesign or the installation of a pool.
The advantages of winter planning are manifold. Many horticultural businesses grant early booking discounts of 10 to 15 percent, and you secure the best dates for spring 2026. There is also enough time to prepare the soil optimally for the coming changes. A soil analysis in early spring provides important data for further planning.
Learning to understand your own soil
Before you plan any major changes in your garden, you should know exactly what your soil is like. The classic spade test also provides you with important information in winter when the weather is frost-free. To do this, dig about 30 centimeters deep into the ground at various points and examine the soil.
You can recognize good conditions for your garden planning by crumbly, dark soil without waterlogging that has an even structure down to a depth of 40 centimetres. If there are no compacted layers and there is good natural drainage, you have ideal starting conditions, especially if you are planning a pool.
Challenges that you should include in your planning are compacted clay soil that requires additional drainage measures, very sandy soil that requires intensive humus build-up, or areas with waterlogging that require a well thought-out drainage system.
Soil preparation for different garden areas
The special situation in the pool area
The floor around a planned pool must meet special requirements. It should drain water reliably, be sufficiently stable and still offer the opportunity for attractive planting. A drainage layer of gravel is recommended for clayey soils, while the actual compaction should only take place in the direct foundation area. For border planting, plan a distance of at least 50 centimetres from the edge of the pool and use high-quality, humus-rich substrate.
The soil excavated during pool construction, often between 40 and 60 cubic meters, can be used for terrain modelling with clever planning. It is important to store the valuable topsoil separately and reuse it later. In this way, you can turn a necessary construction project into an opportunity to optimize your garden.
Investments in various garden areas
| Garden area | Soil preparation | Cost/m² | Optimal planting time |
|---|---|---|---|
| Vegetable bed | 30 cm compost-soil mix | 15-20€ | April-May |
| Perennial bed | 20 cm planting substrate | 10-15€ | March-April or September-October |
| Pool surroundings | Drainage layer plus substrate | 25-30€ | After completion of pool construction |
| Lawn area | 15 cm turf base layer | 8-12€ | April-May or September |
Composting as a long-term investment
Creating a compost system in winter lays the foundation for valuable humus, which will be available to you when landscaping your garden in 2026. A well-designed compost system transforms kitchen and garden waste into high-quality fertilizer and closes the natural cycle.
A semi-shaded, easily accessible spot is suitable for the location, which should be facing away from the wind if a pool system is planned. A base area of around 1.5 by 1.5 meters is completely sufficient for a 500 square metre garden. The optimum mixture consists of around 30 percent nitrogen-rich green materials such as kitchen waste and fresh cuttings, 60 percent carbon-rich brown materials such as leaves and shredded material and 10 percent starter in the form of finished compost or garden soil.
If you set up your compost area now in winter 2024/25 and start filling it for the first time in spring 2025, you can use finished compost for your new system as early as spring 2026 after moving it in fall 2025. This forward planning pays off with considerable savings on fertilizer and soil conditioners.
Mulching as a universal soil care strategy
Mulching mimics natural ground cover and fulfills several important functions in the garden. A well-thought-out mulching strategy saves water, suppresses weeds and continuously improves the soil structure. When planning your garden, you should consider mulch areas from the outset and match the material to the intended use.
In areas close to the pool, mineral materials such as lava mulch or gravel with a layer thickness of 5 to 7 centimetres are recommended, as these do not cause any organic contamination of the pool water. Chippings are particularly suitable for paths as they are clean and easy to maintain.
Organic mulch materials, on the other hand, are used in planting areas. Bark mulch with a thickness of 7 to 10 centimetres is ideal for woody plants and shady areas, while bark humus with a thickness of 3 to 5 centimetres is ideal for perennial beds. In the vegetable garden, use free grass cuttings in thin layers of 2 to 3 centimetres or straw with a thickness of 5 to 10 centimetres, particularly suitable for strawberries and tomatoes.
Planning for rainwater as a valuable resource
Integrating rainwater management into garden planning is now a standard part of sustainable garden design. Installation during the construction phase saves considerable costs compared to retrofitting at a later date and enables optimum integration into the overall concept.
A basic system with two to three 300-liter rain barrels costs between 500 and 800 euros and saves 50 to 80 euros a year on water costs. If you want more convenience, invest 2,000 to 3,000 euros in an underground tank with a capacity of 3,000 to 4,000 liters, including pump and irrigation system. This reduces the annual water costs by 100 to 150 euros.
Premium systems with cisterns with a volume of 6000 to 8000 liters cost between 4000 and 6000 euros, but in addition to automatic garden irrigation, they also offer the option of a house connection for toilet flushing or a washing machine. The annual saving here is between 200 and 300 euros. Pool owners can also channel the overflow water into the cistern and thus save even more fresh water.
Make good use of the waiting time with green manure
While your garden is waiting for the planned 2026 redesign, you can use the time with targeted green manure to improve the soil. This living soil treatment loosens compacted layers, enriches nutrients and protects against erosion.
For spring sowing from March to May 2025, phacelia is suitable as a bee pasture and soil loosener, lupins as a nitrogen collector with deep roots or fast-growing mustard, which is also effective against soil pests. In late summer between August and September 2025, sow winter rye for erosion protection and humus build-up, incarnate clover for nitrogen fixation over winter or lamb’s lettuce as edible green manure.
Practical procedure for your winter planning
The first step should be a professional soil analysis, which you can order for 30 to 50 euros in January or February. This forms the basis for all further targeted improvement measures. At the same time, set up a composting area in winter and start collecting kitchen waste so that you have ready-made compost by 2026.
Contact garden planners between January and March to secure early booking discounts and reserve the best dates for 2026. When planning the rainwater system, you should integrate it into your overall concept from the outset and check possible subsidies, which can be up to 4000 euros depending on the region. Order seeds for green manure in February and sow them from March.
How much high-quality topsoil is needed after construction work?
For lawns, expect 15 to 20 centimetres, for flower beds 30 to 40 centimetres and for planting shrubs 50 to 60 centimetres. The cost of good topsoil is between 20 and 30 euros per cubic meter. For an average garden of 500 square meters, you should calculate with 15 to 25 cubic meters of topsoil and costs between 450 and 750 euros.
When is the optimum time for soil improvement measures?
Ideally, you should start 12 months before the planned planting. For a new planting in 2026, you should start in spring 2025 at the latest. Composting takes 6 to 9 months, green manure is already effective after 3 to 4 months. Soil analysis is best carried out in late winter or early spring when the soil is not frozen.
What are the benefits of a professional soil analysis?
The investment of 30 to 50 euros enables you to take targeted measures instead of the watering can principle and saves 200 to 500 euros in the long term by avoiding bad investments. The analysis shows the pH value, nutrient content, humus content and any pollutants. You can use this data to apply targeted fertilizer, correct the pH value and select the right plants.
How long does it take for the soil quality to visibly improve?
The first positive changes can be seen after just 3 to 6 months by mulching and adding compost. After a year of continuous care, the improvement is clearly noticeable: the soil becomes looser, stores more water and plants grow more vigorously. A fundamental transformation from poor to good soil takes 2 to 3 years if all measures are applied consistently.
Can I use pool excavation for soil improvement?
This depends on the soil layer. The top 30 to 40 centimetres of topsoil should be stored separately and reused. Deeper layers are suitable for terrain modeling, mounding or as a substructure for paths. Loamy excavated soil mixed with sand and compost can be used as a planting substrate. Pure gravel or sand is suitable as drainage material. Important: Never use compacted subsoil directly as planting soil.
How much water can I really save by improving the soil?
A humus-rich soil with 5 percent organic matter stores around 10 to 12 liters more water per square metre than a humus-poor soil with 2 percent. For 200 square meters of planting area, this means 2000 to 2400 liters of additional storage capacity. In practice, the amount of watering required is reduced by 30 to 40 percent, which corresponds to savings of 60 to 100 euros per season. Combined with mulching and rainwater harvesting, you can halve your water costs.