Monty Don, Alan Titchmarsh and others predict space, seed and plant shortages - and the need to make gardening greener.

Gardening became a saviour to millions during 2020 as people had a go at growing their own veg, learning planting know-how and nurturing new houseplants.

So, what are the challenges gardeners face as we go into 2021? Our most famous green-fingered gurus offer their views.

Monty Don

"On a very basic level, the challenge is space. By the time I was in my early 30s I was on to my second garden of my own," says the Gardeners' World presenter, whose latest book My Garden World has just been published.

"But young people my children's age, in their early 30s, don't have houses, they don't have gardens - it's having the opportunity to garden.

"If young people have the energy and the desire to change things but don't have access to gardens, like we did, that is a big challenge.

"Climate change is something that is affecting gardeners as much as anyone. It's not necessarily disastrous but it is a change and it's difficult."

Alan Titchmarsh

The gardening guru, whose latest poetry book Marigolds, Myrtle and Moles: A Gardener's Bedside Book provides a much needed escape, says: "One good thing that did come out of 2020 was the realisation that gardens had an enormous part to play in not only preserving the sanity of the nation, but also in providing food.

"More folk than ever decided to grow their own fruit and veg. Thankfully, in spite of being closed at the beginning of the first lockdown, garden centres were opened just in time before the spring turned into an absolute disaster for British growers and British horticulture - worth around £24 billion GDP to the economy, and priceless in terms of our physical and mental wellbeing.

"I do hope that the legacy of this year - and the solace and stimulation that has been provided by gardens and gardening - will have a lasting effect on our attitude to growing things, and that future generations will see gardening for what it is - the sharp end of caring for the environment, albeit on a small scale at local level. It really does matter, and it really does make a difference."

Sarah Raven

"With new research pointing to the immunological benefits of Vitamin D, being outside, growing and gardening is set to rise further, says the gardening broadcaster and author, whose new book, A Year Full Of Flowers is due to be published by Bloomsbury on March 4.

"Uncertainty about the future makes planning anything hard, and that includes the garden. There are longer than usual waiting times for things with greater demand for stock and fewer people out there able to grow and/or deliver the plants you want or need.

"And with Brexit, plant availability and prices are less certain. What will happen to the euro/pound exchange rate? Will there by tons of waste? Will there be lorries held up full of plants coming from the continent needing water? Growing your own is the best way to keep at least some control."

Michael Perry (aka Mr Plant Geek) and Ellen Mary

The co-hosts of The Plant Based Podcast say: "This year has been a challenging, yet enlightening, year for horticulture. While supply had its own challenges, interest in growing reached a peak. The world of mail order excelled and opened up a range of plants you couldn't buy in the garden centre.

"Fingers crossed, 2021 will see further interest in horticulture, if not inhibited by availability. Our hope is that we can entice houseplant lovers to consider their outside spaces, patios if they have them, or window boxes.

"Indoors, we'd like to see a move to flowering houseplants, which opens up the world of orchids, calandiva and some super sparkly chrysanthemums. Outdoors, innovations for growing veg will make home harvests the norm."

Lucy Start

The SheGrowsVeg influencer with 105,000 followers on Instagram says: "When the first lockdown struck, suddenly the country found itself housebound with little to do and the garden, balcony or resident houseplant family quickly became the perfect way to pass the time.

"People who had never had much interest in gardening in general abruptly embraced the pastime with fervour and the scarcity of seeds, plants or just a simple bag of compost at the start of this year's growing season is testament to the sheer numbers of people getting involved.

"The greatest challenge facing the gardening world in 2021 is to turn this sudden influx of gardening newbies into long term converts. To do this, there needs to be more ways for all people to grow, more focus on how to grow when you have little or no outside space and efforts made to keep the innovation and energy that has appeared this year alive and engaging."

Chris Collins

The head of organic horticulture at charity Garden Organic and former Blue Peter gardener says: "Looking back, suddenly I had all this time for walks, looking at plants and tons of time on the allotment. I've never eaten so well.

"Some people will refer to 2020 as the year of Covid. To me, though, it will always be the year of the tomato as I never cropped so many."

"The biggest challenge is maintaining the march toward a more natural style of gardening and further imbibing it into the mainstream norm. Younger gardeners in particular are much more aware that a garden is a shared space and needs the balance of both nature and plant care.

"Many new gardeners will be small space urban gardeners and we will miss a trick if we don't engage and retain them."

Frances Tophill

The Gardeners' World regular and author of Rewild Your Garden says: "People have got more into gardening, especially growing their own food, but on a broader scale people have become so much more aware of environmental issues and sustainability and a kind of perspective on the world from Covid.

"If 2021 is anything like this year, getting hold of seeds will be challenging. The demand was huge last year - just ordering them was a challenge.

"But sustainability is the biggest challenge, and the industry of horticulture keeping up with people's awareness of not using peat, not importing plants from all over the world without any idea of where they've come from, recycling our plastic pots and all those sorts of issues, as well as the waste that's involved in horticulture and the lack of transparency of the industry and how sustainable it is."

Pippa Greenwood

The regular panellist on Gardeners' Question Time and grow-your-own expert at pippagreenwood.com says: "If you can say that Covid-19 had an upside, for me it was that so many people discovered gardening for the first time, and many re-found it after a long break. It's up to all of us who are already hooked to ensure that we pass on help, hints, tips and inspiration at every opportunity.

"As for challenges, I do have concerns that there could be plant shortages, partly because of Covid, but my fear is that the new border controls and proposed plant inspections, import regulations and all the costs involved could have a far bigger impact.

"For many reasons (and certainly in terms of actual carbon footprint) we simply cannot grow all the plants gardeners want in the UK, basic things like day-length, seasons and temperature mean that growing some of what we want would not be acceptable from an environmental perspective.

"These EU-exit effects are also likely to cause a hike in the prices we see in garden centres and nurseries."