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Verbascum Southern Charm

Why is Spring equinox so important ?

It is such a crucial date in the gardening calendar for zones which are not very close to the equator - the UK is a classic example and gardeners need to bear this in mind when sowing seeds. 

 

Equinox falls twice a year, once in Spring - Late March and again in Autumn - Late Sep , this is the time that night and day become equal. There is a slight discrepancy on the exact date, due to various astronomical reasons which I will not bore you with right now as the most important thing to remember for spring Eqinox is that short winter days are disappearing and the long days of summer are on their way. You will begin to see a surge of growth and activity from plants in the garden and seedlings sown earlier in the year as many plants respond to the lengthening of days of spring and the shortening cooler nights very well. It is such an important response that it has its own name, photoperiodism.

Each plant has its own inbuilt regulated response to the length of day and night. Some plants like more daylight hours, some less and others like equal length so these form 3 distinctive groups. Short Day plants, Long Day plants and Day neutral plants. Short day plants will flower best when day lengths are below a certain number of and vice versa for long day plants. Day neutral plants will flower when they are ready and are not really affected by light so much.

 

Short day plants :These flower later in the season, during late summer, autumn and winter as they do not like long sunny days and prefer longer nights:

Dahlias

Poinsettias

Chrysanthemums 

Amaryllis

Hellebore

Daffodils

Camellias

Winter jasmine

Cyclamen

 

Long day flowers which like to wait for longer daylight hours

Foxgloves

Hibiscus

Gypsophilla,

Sunflowers

Cosmos​

Cornflower

​California poppies

Nigella

Day neutral plants will flower when they ready:

Marigolds

Geraniums 

Petunias

Zinnias

Impatiens 

Begonias

Nasturtiums​

Verbena

 

Gardeners can of course use artificial lights and controlled environments to manipulate the day and night length and increase the growing season. Daylight lamps will force rapid growth in seedlings but the cost of this to the home gardener usually outweighs any benefit on such a small scale. For flower farmers it may give a crucial extension to the season to make the business viable. 

For the average gardener it important to remember that seedlings will need light to grow into healthy plants. Starting them off too soon in the depths of winter may mean that they just don't receive the right amount of light they need to perform at their best.  Many of the annuals we sow for cutting fall into this category and they will get leggy, stretching for the light and become sickly. By waiting until the equinox to sow seeds, they will perform better and often outperform earlier sowings overtaking them and seed packets will give a good indication of when seeds can be started. Our guide Seedling Success gives more tips on how to nurture seedlings successfully for a bountiful harvest. 

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