The time to plant bulbs is now. Keukenhof is closed and tulip season in Holland is over. No need to feel sad though. On the contrary. It’s time for a celebration. 

tulip season over sad happy dahliaTogether with Dutch flower farmers & gardening lovers I look forward to Mid-May. This is the moment to prepare for a new flower season. The bicycles and boats are being washed, new menus full of typical Dutch food and seasonal products created. And it’s time for the flower growers and – amateur- gardeners like me to plant Dutch bulbs. 





Spring or fall: what’s the best time to plant bulbs?

Tulips are the best known Dutch bulbs. Dahlias are making their comeback. Whereas the tulip flowers in spring, the dahlia flowers in fall. The funny thing is that when the tulips have come to full bloom it is time to plant the dahlia. And when the dahlia flowers it’s time to plant the tulip. So when you come on the cycling tour Keukenhof area to admire the dahlia or tulip fields, keep your eyes open. The bulb grower might just be planting his bulbs in the fields around his flower farm Holland. 

Besides the flowering season the biggest difference between the spring and summer bulb is their relationship with frost. Where a tulip needs a period of frost to grow and bloom, summer bulbs can´t stand frost. The ideal time to plant bulbs that flower in summer is when the soil temperature is around 13°C. If the soil is colder, the Dutch bulbs might not grow. Or, even worse, they might rot. 

summer bloom Holland flower field best time Keukenhof visitWhat are the main Dutch summer bulbs?

In the past growing summer bulbs in Holland was a side activity. All the attention went to tulips, daffodils and hyacinths. All other bulbs and tubers were an extra. In Dutch called bijgoed. Nowadays when you visit the Keukenhof area in summer you see flower fields in all colors of the rainbow. Callas, gladiolus and lilies fill field after field. Mid summer and fall – Indian summer-  is when you’ll spot most dahlias. Dahlias are actually not bulb flowers, but tubers. If you want to be more precise, the dahlia is a tuberous root. They store their nutrients in the root and their structure is similar to that of a potato. One tuber can give multiple flowers.

beach & dahlia bike tour Verita's Visit guided

Why Ice Saints should be on your gardening calendar

As said Mid-May is a time to look forward to. When the tulip season is over and Keukenhof closed it is the time to plant bulbs from Holland. Summer bulbs and tubers. It is said that farmers and gardeners in 1000 AD already used the name days of the four Ice Saints as a reference point for planting summer bulbs and young plants. The name days of the saints fall on 11- 15 May. These dates are seen as the last days frost at night can occur. Although it still can be quite cold after the 15th of May, chances of frost at night are much smaller. So, if you want a colorful border in your garden or a full flower field in bloom in summer and fall, wait till the 15th of May and plant bulbs then.

Can I plant bulbs and summer tubers earlier in spring?

Of course as a flower fan and amateur gardener I understand it is very tempting to start creating your dahla garden as soon as the first rays of sunlight announce the start of spring. So if you really can’t wait, start planting those summer bulbs earlier in spring. But, it is not the best time to plant bulbs flowering in summer in the garden. Plant your summer flower bulbs in a beautiful pot and keep them indoors. Then, after the Ice Saint’s Mid May, you can choose to replant them to create the summer flower bed of your dreams.

time to plant bulbs dahlia hollandWhen do dahlias flower?

Dahlias come in many shapes and colors. Most of them start sprouting within 5 weeks after planting the tubers.  Some of the things to have in mind when you plant summer bulbs and fall tubers are the weather, the variety, the location in your garden. These all play a role in when the dahlia flowers and how big the flower becomes. The early varieties will bring color to your garden Mid-June, but there are also varieties that bloom as late as December.

keukenhof area dahlia tour verita's visitWhen should I buy in time to plant bulbs for summer flowering?

Just like tulips it is best to buy your Dutch dahlia tubers and summer bulbs directly from the grower. You can buy them at the moment you come on a bike tour Keukenhof area in spring. I will take you to locations where you can order them. You don’t have to visit Holland though, you can also buy them online and then the summer bulbs and tubers will be shipped to you in March. As the dahlia season is from June till December I definitely do not recommend buying the summer bulbs in that period. The bulbs and tubers will be from last season and the risk is high that when you plant bulbs they don’t come to – full- bloom. 

Recommended tours:

beach & dahlia bike tour Holland summer

Leiden tulip bike tour flower farm & windmill stop


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