The most important tips for May

1. Balcony, terrace, garden and house entrance: there is room for the colorful balcony plants everywhere. Now the choice is the greatest!
2. From mid-May, the warmth-loving vegetables can be planted outdoors, in sufficiently large pots also ideal for balconies and terraces.
3. Now is the ideal time to sow many vegetable seeds directly outdoors.
4. Hedge plants, lawns and evergreen plants are watered regularly during prolonged droughts.
5. With insect houses you offer the useful helpers a valuable place to stay.
6. Start of the season for dahlias, gladioli and canna. If planted in time, the lush summer bloomers will delight for many months.

ornamental garden

Colorful and versatile in flower shape and color, Japanese azaleas and rhododendrons are now pleasing. These easy-care shrubs present themselves in the garden and in large tubs with lush flowers. Discover the new varieties and plant them right away in Kölle’s Beste Rhododendron soil. If you haven’t already done so, now is the time to supply existing plantings with Kölle’s Beste Rhododendron fertilizer. Only adequately nourished plants are floriferous, vigorous and robust.

On tulips, daffodils and hyacinths, only the dried parts of the flower are removed after flowering. To do this, cut off the flower stalks just above the leaves. This prevents unnecessary seed formation and the energy is stored in the bulbs. In addition, strengthen the bulbous plants with a dose of «Flower Bulb Power».

Plant dahlias now, the variety of varieties leaves nothing to be desired. Ideally, you put Kölle Bio Root Power in the planting hole, this is a simple way of promoting root formation.

Forsythia, spar and blood currant are pruned every two to three years after flowering. Here you cut out the oldest shoots and thus rejuvenate the robust trees. Sharp scissors are important for a clean cut. You can also read about early bloomers in our blog «Which shrubs bloom in spring? »

Lilacs bloom in May, a classic for the natural garden. With its incomparable scent, the easy-care wood enchants year after year. The tree grows shapely without pruning, ideal for sunny to partially shaded locations. New varieties remain small in growth and are therefore ideal for the front garden or large containers on the balcony and terrace.

Check your box plants weekly for box tree moth caterpillars. If the infestation is low, collecting the voracious caterpillars is the best solution. You can also read “Protecting box trees properly” in our blog.


The orchard is very easy to care for in May. It is important that new plantings are supplied with water in the event of a prolonged drought. This also applies to strawberries and other berries.

Now is the time to plant strawberries, raspberries, blackberries, grapes and kiwi. With a sufficiently large planting hole and high-quality Kölle’s Beste planting soil, you give the trees the best start. Table grapes and kiwi are ideal for facade greening, with climbing aids they serve as privacy screens on balconies and terraces.

In the middle of the month, strawberries are mulched with straw or wood shavings. This protects the fruit from dirt and keeps snails away. You can also read our blog «Gardening pleasure instead of snail frustration».

Regularly remove the weeds under the fruit trees. A thin layer of mulch is also beneficial for soil life. A green carpet of nasturtiums helps retain soil moisture and naturally minimizes lice.

Rhubarb can be harvested regularly. Here it is better that the stems are twisted and not cut. Leave a few stalks as this is the only way you can harvest again next year. The last harvest date is June 24th, because the oxalic acid content increases extremely in summer.

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Herb and vegetable garden

You can now start sowing the cucumber plant, zucchini, melons and beans outdoors. For many other species it is also time to sow. You can find more useful information about the vegetable garden in our vegetable sowing calendar.

Heat-loving vegetables such as tomatoes, peppers and aubergines are planted outdoors from the beginning of May, depending on the weather. A raised bed and foil house is ideal for this, because the soil heats up even faster here and the plants thank you with lush growth.

Basil — the classic of the herbs convinces with its characteristic aroma. Our nursery offers a variety of vigorous plants. Get to know the fascinating plants and learn the differences between Cuban shrub basil, Greek basil, Russian basil and many other varieties. Would you like to successfully sow basil yourself ? It should be noted here that the herb seeds are not covered with soil. As a light germinator, the seed needs 15 to 20 days at 20 to 25 °C until the plants are visible as seedlings.

Vegetable sowings from March and April are now isolated. To do this, plants that have grown too densely are removed. This ensures that the remaining plants develop better and have enough space to grow.

Rich treasures are growing in the herb garden. Chives are washed, finely chopped and placed in ice cube trays. Fill the last third with water and freeze the containers. The homemade herb cubes are ideal for autumn and winter, when they are added to soups and stews just before the end of the cooking time. On the subject of preserving herbs, also read our blog «Preserving the full aroma of aromatic herbs now».
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balcony and terrace

Now is planting time for all summer flowers. For nature lovers there are many ideas for bee-friendly plants for the balcony and garden. With the right selection, these plants provide valuable nectar for insects all summer long.

Container plants are now brought out of their winter quarters. For better acclimatization, the plants must be gradually acclimated to outdoor conditions. Ideally, the plants are brought out onto the patio on cloudy days. For optimal development, repotting in larger containers is advantageous, and special Kölle’s Beste potted plant fertilizer also ensures an adequate supply of nutrients.

For a feel-good climate on the balcony and terrace, climbing plants offer optimal privacy. Whether as an annual plant or with climbing hydrangeas, kiwi, table grapes and much more — with green walls your own wellness garden will quickly become your favorite place after work. Order bedding and balcony plants easily and conveniently.

You don’t have to do without water on the balcony or in the garden either. Experience the special flair and relax with the refreshing element of water. Our “Fascination Garden Pond” adviser will give you valuable tips and specialist knowledge, also on the subject of patio ponds.

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crop protection

With mixed cultures you prevent certain diseases and pests in a natural way. Note the compatibility between the individual plants and take advantage of the benefits. You can find out everything you need to know about mixed cultures in our “Vegetable plant partners” table.

Create a home for beneficial insects. Insect hotels offer the little helpers a perfect retreat. The lacewings, earwigs and bees that live wild in the garden are responsible for pollinating the flowers and help with natural pest control.

With Kölle Organic Plant Treatment you help the plants’ own immune system and sustainably reduce the infestation of plant pests and fungi. Above all, protect your roses as a preventive measure.

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indoor garden

Many indoor plants can spend the summer in a sheltered spot on the balcony or patio. It is important to get used to the sun’s rays step by step.

Spoil your green plants and fertilize them in May with high-quality Kölle’s Beste Green Plant Fertilizer. You can also wipe the leaves with a damp cloth or rinse them lightly.

Enjoy the mesmerizing blooms of the hibiscus. Colorful and with a unique shape, they bloom in a sunny spot indoors or in a sheltered spot outdoors.


You can obtain clear pond water through various measures. Above all, preventive cleaning prevents contamination and minimizes unwanted algae growth.

The range of aquatic plants is now the largest. Oxygen plants improve the oxygen content in the pond. There is also an assortment of water lilies for small ponds, which do well with a planting depth of 20 to 50 cm.

When feeding fish, it is important that the amount of food can be consumed by the fish within a short period of time, because leftover food affects the biological balance of your garden pond.

garden pond


It’s still the ideal time to lay a new lawn. The seed germinates optimally at a soil temperature of over 12 °C and you will have a lush green lawn in just a few weeks. It is important that the seed is not heavily covered with soil, because grasses germinate in the light.

Regular mowing is essential for a healthy, dense lawn. During the main growing season, you should mow at least once a week.

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