Scotland is about to burst into colour with the start of the second annual National Gardening Show. Its three-day run starts tomorrow at Strathclyde Park and looks set to top last year's 60,000 attendance.

''Ticket sales are up more than 12 per cent on last year,'' said show manager Susan Oliver. ''We have more stands, more marquees, more than 380 exhibits - with some 2,000 people manning them. The horticultural world saw last year's show as such a success that we had twice as many applications for space as we could accept.''

Now established as the highlight of Scotland's gardening calendar, the show will bring together more than 70,000 trees, flowers, plants and shrubs from all over the world. A number will be new varieties making their public debut - but only after 11am, tomorrow's opening time. ''That's deliberate - an hour later than last year's show,'' said Oliver. ''We want to avoid any repetition of last year's traffic problems, keeping show traffic separate from ordinary rush-hour traffic. We mean it when we say don't come early. The car parks won't open until after 10am.''

All types of garden enthusiasts are expected - from experts to complete beginners - and everything, from stand layouts to extended facilities for the disabled, have been designed to meet the anticipated record attendances.

Those who do come will see British horticulture at its best, believes Oliver. ''Within Scotland, the show's success is already creating a greater interest in horticulure, with more people working to achieve exhibiting standards.

''At the same time, the Scottish public want to experience something of what is seen at places like the Chelsea Flower Show - from the blooms, the gardens and the large displays down to the compact, often domestic-size world of the Petit Jardin. Achieving that is one of our aims.'' UK membership of the Royal Horicultural Society has soared by nearly 50,000 to more than 250,000 since last year's Scottish show.

Oliver modestly sees her job of show manager as looking after ''plants, pots and people''. Her colleague John Ridge, operations manager, describes his remit as ''tents, traffic and toilets''. With a small staff, they now operate from permanent offices within the park.

''Last year's show put us all on a very steep learning curve, particularly in discovering what people most wanted to see,'' said Oliver. ''But organising the show is one thing, what the weather might do is something else.

''For the last couple of weeks I've checked every weather forecast, said a few prayers - and had some earnest talks with a couple of amateur meteorologists who are exhibitors.

''If the forecasts prove right, I'll be happy. If it rains, we have an increased number of marquees - and almost all the paths are on hard standing so that there's not too much risk of mud on shoes.''

Oliver's grandfather was a horticulturist but she came to the show via a course in managed events organisation at Kirkcaldy College, summer work at the Edinburgh Festival Fringe and the Glasgow Garden Festival. She also worked for the Royal Highland Society and organised trade stands at the Highland Show for six years before moving to the RHS.

''Being show manager with the National Gardening Show gives me an opportunity to collect many wonderful gardening ideas. I've developed some thoughts about redesigning our four-acre garden in North Berwick. But at the moment I have to struggle to manage any time to work in it.''

One of her tasks is to sit with members of the National Garden Show committee as they scrutinise applications from would-be exhibitors.

''We go for quality. This year, for in-

stance, we have 13 outdoor plant exhibits. We could have had 26 - but that number might have jeopardised our standards.

''I believe the RHS will develop a growing role in Scottish horticulture - with more events, shows and maybe a permanent RHS garden. An army of Scottish gardeners would love that.''