Craven College horticultural lecturer Michael Myers provides his May gardening journal

THIS time last year I was bemoaning the late, overnight frost that had blackened the new leaves on my beautiful pieris. This year the weather has gone one better with not only cold temperatures but snow.

With the Harrogate Spring Flower Show just over, I recall one year in the Valley Gardens when late snow collapsed the main marquee, fortunately not something that has happened since.

It is easy when there is a warm spell in the spring to get complacent and challenge the conventional wisdom in gardening. Garden centres and DIY stores all tempt us with cheap bedding plants and tender vegetables but unless you can protect them from the frost, leave them there.

Few people have heated greenhouses but many bedding plants will survive in an unheated greenhouse if covered with horticulture fleece on cold nights but do not plant them outside until the end of May.

I am all for products that help to encourage people into gardening and have been intrigued by recent adverts for Miraclegro Groables. The product not only contains seed but also compost and fertiliser, all you have to do is plant it in the garden (presumably now), sit back and wait for a guaranteed bumper harvest. You can chose from tomatoes, peppers, cucumbers and indeed a whole range of crops that are likely to fail grown this way.

I will, however, reserve judgement and it will be interesting to see whether this product is successful or not. I do worry though that horticulture is being dumbed down by large companies.

Growing crops has been at the centre of human civilisation for millennia and yet you would imagine that the skills for growing food are more complex than filling out your tax return.

The recent introduction of tomatoes grafted onto potatoes was an interesting novelty but an expensive way at £10 a plant of growing both crops. That amount of money would buy perhaps 80 seed potatoes with change for a packet of tomato seed and a much greater chance of a worthwhile crop.

You do not need an allotment for potatoes, indeed they can be grown in a wide range of containers.

At college, however, we have opted for the traditional method with rows of first earlies and maincrops having been planted now for several weeks. Soon the young shoots will be appearing and the process of earthing up can begin.

Piling soil on top of the emerging shots may seem odd but it not only protects them from the frost but helps to prevent the potato tubers from turning green. There are the additional benefits of controlling weeds and holding moisture around the plants too.

Alternatively you can avoid having to earth up if you grow the potatoes under black polythene. Last year keeled slugs damaged a lot of our potatoes, especially the maincrops and are unfortunately difficult to control since they spend most of the time underground and so are unlikely to come into contact with slug pellets.

Some varieties such as Charlotte seem to be less susceptible but later harvesting can make the problem worse and so this year we will check the tubers regularly for damage and harvest them before they are spoilt.

April has been a busy month for plant sales with the Harrogate Flower Show, Harlow Carr Plant Fair and others all being staged. Against my better judgement I did succumb to some new purchases including a lovely form of honesty with purple leaves named after Rosemary Verey.

Honesty is an under-rated garden plant with its pretty flowers and attractive seed heads, there are several forms with variegated leaves too but this was the first one I had seen with deep purple leaves.

From the same vendor I also bought a variegated form of the perennial honesty called Partway White and a named form of Cardamine heptaphylla, a refined relative of hairy bittercress. I already grow a few forms of this pretty woodlander and it has been suggested that I name one of the selections and so it looks as if Cardamine heptaphylla ‘Helen Myers’ may be available soon.

The next plant sale in my diary is the Newby Hall Plant Fair on Sunday although our colleagues at Ripon Walled Garden have their annual plant sale on Saturday from 10am to 4pm.

On my roadside verge, the daffodils are nearly over but yellow trout lilies, Erythronium ‘Pagoda’ are starting to appear. Like many spring woodlanders the flowers are ephemeral and a few days of warm weather will quickly see them over until next year. Just as well there are lots of other things to follow.