Many gardeners and the wider public will be visiting an open garden this year, one which is opened to the public on one or more specific days of the year to raise money for nursing and caring charities.

The National Garden Scheme, which is celebrating its 90th birthday this year, remains the biggest charitable funder of both Macmillan Cancer Support and Marie Curie.

Its president is high-profile baker and gardener Mary Berry, who has opened up her own NGS garden for 20 years, while the scheme has undergone a revamped image which is more informal than the old one and a newly designed 'Yellow Book' - which lists details of this year's open gardens.

It has just announced that £3 million will be donated to its beneficiaries in 2017 as a result of funds raised through garden openings in 2016, and George Plumptre, the charity's ebullient chief executive, explains: "In our 90th anniversary, it's wonderful to celebrate all our new gardens coming in, but also look at the gardens which opened 90 years ago and are still open - even Sandringham, thank you, Your Majesty!"

This year, 3,650 gardens will be opening for the scheme, including more than 500 new and returning gardens, 270-plus groups of gardens, 38 allotment groups, 15 school gardens and 10 hospice gardens.

When the scheme started in 1927, two gardens opened on Whit Sunday - Hatfield House in Herts and Sandringham, Norfolk. The Times sent a photographer to Hatfield House, capturing the first visitors.

"What interests me is the way that we represent how gardening has diversified. In the 1920s most of our gardens were country houses, country cottages - all rural," enthuses Plumptre.

"One of the fascinating things is that a number of gardens, like Great Dixter, a famous garden in Sussex and the famous home of Christopher Lloyd, and Sissinghurst (Kent), which is even more famous, were brand new when they first opened before the war and now, in our 90 years, they have grown to become national icons.

"In 1980, there were 30 gardens opening within the M25 and today there are 300. It's that growth of diversity which reflects how people garden. Many more of our owners do all the work themselves. In the 1920s most of the gardens that opened relied on gardeners. Today, you do it yourself and so when you open, it's the fruits of your labour that people are seeing.

"City gardens are developing slowly, which is really exciting. Groups of gardens in villages is another really important development of recent decades."

He says it is still sometimes a challenge to get people to open up their gardens to the public just for one or two days of the year.

"We always visit a garden to have a look before they open. Everybody thinks there's a certain stamp of quality if you are opening for the National Garden Scheme.

"We do get a number of people who say, 'Oh, I couldn't possibly open up my garden to the public for the National Garden Scheme because I'm not nearly good enough' and then you find that actually they're one of the best. Gardeners are very modest folk. They don't push themselves forward. It's normally a friend who says, 'You must go and see that garden'."

Do you think your garden could be opened to the public for the NGS? Or do you just want to visit one of the open gardens? To find details of all gardens opening near you, visit the NGS website www.ngs.org.uk or download the free NGS 'GardenFinder' app.

Scotland's Gardens (www.scotlandsgardens.org) runs a similar open gardens scheme to raise money for charity

Ulster Gardens Scheme (www.ulstergardensscheme.org.uk) holds open days to help raise funds to support work in National Trust gardens in Northern Ireland.

The NGS 'Yellow Book' is available from all good bookshops and all counties have their individual booklets, which can be picked up via the NGS website www.ngs.org.uk

Best of the bunch: Hyacinth

These gorgeous spring bulbs are famed as much for their heady fragrance as their colourful showy spikes of flowers in shades ranging from white to deep purple.

Among the best blue flowered varieties is Hyacinthus orientalis 'Blue Jacket', which bears waxy deep blue flowers with purple veins, and 'Carnegie', which is white. Plant them in early autumn for March or April flowering - but avoid touching the bulbs with your bare hands as they can cause allergic reactions - in deep, well-drained fertile soil in sun or partial shade, 10cm deep and 7.5cm apart.

You can plant them closer together in containers and they look amazing in large shallow bowls in single colours. Make sure you place them close to the patio door or an open window which will allow you to inhale their delicious fragrance on spring days. Plants can be lifted once the foliage has died down and stored in a cool, dry place until they are ready to be planted again in autumn.

Best of the bunch: Spring cabbage

You can now have cabbage of one type or another virtually throughout the year if you plan well, but spring cabbage is among the most underestimated of vegetables.

It should be sown in mid to late summer and harvested from February to May the following year. Spring cabbage is a heavy feeder so add plenty of organic matter before you plant and pick a sunny spot.

Sow them in the open ground in seed drills and thin out the seedlings, transplanting the young plants to their final position when they are around 15cm high, in the autumn. The plants should be large enough to survive the winter.

Start cutting alternate plants for spring greens as soon as they are large enough in March. Most will produce firm hearts by late April or May.

What to do in the garden this week

  • Continue to prepare seedbeds outside, weather permitting, using planks to stand on if the soil you are working on is very wet.
  • Weed borders and mulch bare soil with organic matter or other material to stop them emerging again.
  • Plant containers with hardy plants including small trees, shrubs and climbers.
  • Cut vigorous climbers such as ivy, winter-flowering jasmine and honeysuckle back hard.
  • Lift and divide overgrown clumps of summer-flowering herbaceous perennials, just as growth gets under way.
  • Split primulas after flowering, as the flowers go over.
  • Place stakes in the ground to support perennials which will soon be emerging.
  • Cut down growth left after winter to make way for new shoots, dressing the soil with a fertiliser so it's ready for a layer of mulch.
  • Plant out early varieties of potato, once they have been chitted.
  • Plant a patch of comfrey in a bright, sunny corner of the kitchen garden. The leaves make a great addition to the compost heap, or spread over the soil around crops as a mulch.
  • Sow salad leaves little and often, resulting in a continuation of crops to harvest through the summer.