"And now we have a lull over Easter," remarked a regular concert commuter last weekend, emerging from John Suchet's Beethoven night.

Well, not quite yet, I thought, mindful of the fact that this Thursday the BBC SSO has a concert with Andrew Litton, featuring James MacMillan's Second Piano Concerto played by Peter Donohoe and Rachmaninov's evergreen masterpiece of late Romanticism, the Second Symphony.

But it's true that, on the following day, Good Friday, a sense of stillness appears to settle over Scotland's weekly turnover of symphony concerts from the three orchestras. It's essentially just the Easter weekend, extending into the following week, before rehearsals resume for a busy session of concerts, beginning on Thursday April 16 with the BBC SSO and Mark Wigglesworth, a celebrity recital on the Friday lunchtime in the RCS by pianist Pascal Roge, the SCO back in action with Richard Egarr in the evening, and the RSNO turning its lens onto film music on Saturday night with that splendid authoritative guide, Richard Kaufman.

However, that surface calm over the brief Easter period is just that: superficial. Behind that surface there is an almost seismic eruption of activity as Scotland's top young musicians are mobilised, en masse, into an intensive training, coaching and rehearsal period, culminating in a series of flagship concerts that begin on Thursday next week and run right through to Friday April 24.

It happens every Easter and it recurs every summer. It's an important event for the nation's most promising talent: it's their day in the sun; it's the time when all those dogged, killing hours of learning, practising, painful polishing and rigorous, disciplined rehearsals pay off. But it's more than that. It's the future. Some of these youngsters will pursue their training through their teens, into college, conservatoire or university, and will mature into the next generation of Scotland's orchestral musicians. That's not fanciful. It's evolving and happening all the time. I've been watching it annually for 30 years, and we frequently name musicians as they grow and start appearing with the national orchestras.

And from that perspective, the next few weeks are critical, because they will provide a snapshot of where all these youngsters are at this particular moment in their lives and training. Who's involved? Absolutely everybody. Hundreds of youngsters will assemble into orchestras and choral groups, and, in what is effectively a festival of youth, will very possibly take your breath away with what they can do.

There are three National Youth Orchestras of Scotland, organised by age and, flexibly, by ability. Big NYOS, as I call it, with experienced musicians of 25 and under, kick it all off on Tuesday at 7.30pm in the City Hall with the exciting Nicholas Collon conducting Strauss's Macbeth and Rach Two, while composer John McLeod, continuing his fantastically busy 80th birthday celebrations, will direct a revised version of his Piano Concerto with soloist James Willshire. That concert goes to Dundee the following night.

On Thursday afternoon, Christopher Bell, the peerless guru of all things choral, brings the National Boys Choir to the City Hall at 3pm. (The National Girls Choir will appear at St Cuthbert's in Edinburgh on Friday 17.) Then, at the weekend, it's the turn of the Edinburgh Youth Orchestra, who, on their night, can be absolutely stunning. Sian Edwards will conduct them at the Usher Hall on Saturday 11 and the RCS the following night in a blistering programme featuring Tchaikovsky's Romeo And Juliet, Strauss's Oboe Concerto and Berlioz's almighty and wonderfully lunatic Symphonie Fantastique.

The next night, Monday 13, it's the turn of NYOS again, this time the NYOS Senior Orchestra (ages 13-18) who, with regular conductor James Lowe, will appear at Perth Concert Hall (7pm) in a programme including a work by Edinburgh-trained composer Anna Clyne (now resident with the Chicago Symphony Orchestra) and Sibelius's blow-away First Symphony. An unusual one follows on Wednesday 15 in the RCS at 6pm where the conservatoire's top student soloists will be joined by the RSNO and conductor Jean-Claude Picard in a series of concertos. Then on Sunday 19 it's NYOS yet again with the Junior Orchestra (ages 8-13) playing a lovely programme at 4pm in the RCS with young New Zealand conductor Holly Mathieson.

And finally, the concentrated marathon by Scotland's young musicians culminates in the RCS on Friday 24 at 7.30pm with the full RCS student Symphony Orchestra and conductor Garry Walker in a programme featuring Weber and a Mozart piano concerto (played by a prize-winning student) and climaxing with the quintessential dramatic orchestral blockbuster, Beethoven's explosive Fifth Symphony, whose intellectual and musical heroism seems somehow emblematic of this towering Easter display by the country's finest young musicians. Note that at selected venues, NYOS is offering a special £2.50 ticket to under-25s.