Plants are sending out growth as we approach spring. This is the last opportunity to complete any formative pruning. Take the opportunity to manage your plant collection and develop frameworks for the coming growing season before cuts bleed with the flow of sap.
Daphne ‘Spring Beauty’ is indeed a beauty and scented too. An evergreen shrub hybridised in the 1820’s it has a mass of flowers in a terminal cluster. Purple in bud, opening a lighter shade of pink and when open a heavy powerful scent fills the air around and about. Enjoying an open situation Daphne will flower reliably from an early age. Choose a permanent position as they do dislike being transplanted. Ideally sheltered from drying winds and too bright summer sunshine, in soil that drains well.
Colour this autumn has been unrivalled. The warmth from the sun and the dry season have combined to extend the floral season. Take a last walk through the student plots within the demonstration garden. The fresh intake of horticulture students are on the cusp of grubbing everything out to prepare their plots for fresh sowings. Absorb the scent drifting off the Alyssum, a mass of white flowers. Marvel at the tall Cosmos that have not blown apart this year. The Sweet Pea towers still have pickings that would fill vases in the home, albeit with shorter stems. The real stars are two cultivars of Rudbeckia hirta, short lived tender perennials that are best treated as half hardy annuals; sowing, growing, flowering and composting each year. R. ‘Irish Spring’, with yellow petals and a green centre, the heavy morning dew settles on the foliage magnifying the leaf hairs. R. ‘Aries’ with a brown centre and markings radiating out on the petals.
May is a fantastic month in the Edible Garden. It is very exciting to see fresh green growth, fruit blossom and lots of seedlings emerging from the soil. However it is a busy time of the year and there are a lot of tasks to do in the garden such as watering, weeding and sowing.
Young plants can quickly become swamped by weeds. So it is essential to be vigilant. Regularly hoeing is a great technique to keep on top of the weeds. Here at the Edible Garden we use an oscillating hoe which cuts through the weeds in both directions. (see picture)
Most hardy crops can be sown outside now. This includes beetroot, broccoli, cabbage, carrots, cauliflowers, kale, peas, turnips, lettuce, rocket, radish, spinach, spring onion.
Salad leaves and radishes grow very quickly and do not store for long when they are ready. To avoid gluts and provide a regular supply through the season it is a good idea to sow small batches of seed every few weeks. This is known as succession sowing (see picture).
In early May, tender crops such as French beans, runner beans and courgettes can be sown in pots in greenhouse, polytunnel, cold frame or windowsill. They will need to be hardened off (gradually acclimatised to outdoor conditions) before they are transplanted into the garden at the beginning of June when the risk of frosts is minimal.
Towards the end of the month it is possible to sow tender crops outside. If your garden is prone to late frosts it is worth constructing a cloche to protect young plants.
The young shoots of potato plants are very susceptible to frost damage. Protect them by ‘earthing up’ the soil around the stems.
When vegetable seedlings have grown a few leaves it is time to thin them out so they have enough space to grow to their full potential. The recommended spacing for each crop can usually be found on the seed packet or in a vegetable growing book. Select the largest, healthiest seedlings to keep. Gently remove the unwanted plants. To avoid disturbing the remaining plants small seedlings such as carrots and lettuces can be snipped off at ground level using scissors. Water the plants after thinning to re-settle the soil around the roots.
Birds can be a problem in the fruit garden eating buds, flowers and fruit. If possible it is good to net fruit bushes and trees to protect them.
Inspect gooseberry bushes regularly for signs of sawfly larvae that can quickly defoliate the plants. If you spot them remove them quickly.
April is a busy time for the volunteers and community groups that work on the Edible Gardening Project at the Botanics. As the weather improves and the soil warms up it is time to plant seeds outside and watch out for weeds.
There is a great range of seeds that can be sown outside from April onwards, especially if we get a spell of warm, damp weather. Lettuce, beetroot, broad beans, kale, cabbage, turnips, carrots, parsnips, peas, radish, spinach, spring onions and chard can all be sown now. Warm soil promotes speedy germination; if the weather is cold delay sowing. Seed sown later into warm soils tend to catch up with earlier sown crops. To help warm the soil it is possible to cover it with black plastic two weeks before sowing.
It is a good idea to sow your seeds in straight rows and mark the rows at each end with a cane or label. This means the emerging vegetable seedlings are clearly identifiable – weeds don’t grow in straight lines! It should then be possible to hoe between the rows of vegetables to keep the weeds under control.
Young seedlings are very susceptible to being under- or over-watered. Check them regularly, the soil should be kept just damp. Water as necessary with a watering can that has a fine spray.
Once the seedlings are established and have grown a few leaves it is important they have enough space. Seed packets usually contain details about how far plants need to be spaced apart. Thinning out seedlings can feel brutal but it is an essential task for crops to reach their full potential. Water the plants prior to thinning. Select the largest, healthiest looking seedlings to keep. Grasp the unwanted seedlings as close to the ground as possible. Gently pull the plant out of the soil, avoid disturbing the remaining plants. Small seedlings such as carrots and lettuces can be snipped off at ground level using scissors. After thinning your plants water again, this helps to re-settle the soil around the roots. The thinnings needn’t go to waste; you can add them to salads.
Potatoes are a productive and rewarding crop to grow; the best time to plant them is April. To plant the potatoes dig a narrow trench 12.5cm deep. In the trenches place ‘early’ seed potatoes 30cm apart and maincrop varieties 37.5cm apart. The rows should be 60cm apart for earlies and 75cm 30in apart for maincrop. As the potato plants emerge mound the soil over them to protect the leaves from frost. This is known as ‘earthing up’.
The end of the April is a good time to start sowing tender, frost sensitive crops such as runner beans, French beans, courgettes and pumpkins. These can only be planted into the garden once the risk of frosts has past, in Edinburgh this can be as late as June. The seed should be sown in pots in a polytunnel, greenhouse, cold frame or windowsill. Beans have a deep tap root so need to be planted into deep pots, old toilet roll tubes or specialised pots known as ‘root trainers’ are ideal. Courgettes and pumpkins grow very quickly so a minimum pot size of 9cm (3.5inches) is required to prevent them becoming pot bound before they are planted out.
Crops that have been started off early indoors need to be gradually acclimatised to outdoor conditions before they are planted into the garden. This is known as hardening off. Over the course of several days take the plants outside for progressively longer periods of time. After a week or so the plants should be ready to plant out.
March heralds the start of the spring however in Scotland the weather can still be very cold and frosty. Gardening books and seed packets give a range of crops that can be sown from March onwards. In Scotland this advice should be treated with caution. It is best to sow seed once the soil has had chance to warm up. Delay the bulk of seed sowing until April, May and June.
Crops that do germinate at low temperatures include broad beans, peas and some brassicas such as cabbage, kale and radish. When the ground is workable (not too wet or frozen) these can be sown outside in March. Cover with a cloche or fleece to provide some extra protection from the elements.
If your garden is particularly warm and sheltered or you have a polytunnel or greenhouse it may be possible to sow a range of other hardy crops such as beetroot, carrots, chard, lettuce, parsnips and spinach.
Tomatoes, chillies, leeks, celery and celeriac will not germinate at low temperatures but can be sown on a warm window sill or heated propagator to ensure that they have a long season to grow.
Towards the end of the month, if the soil has warmed up, it is time to start planting early potatoes, onions and shallot sets. Early potatoes need protecting from frost so mound up the soil over newly emerged shoots (known as ‘earthing up’) or cover with a fleece if frost is forecast. Newly planted onion and shallot sets need protecting from birds that have a habit of pulling them out of the ground. Cover with a net until they are established.
Other tasks for March include:
- Finish preparing soil; remove perennial weeds and apply organic matter
- Dig in overwintering green manures so they have chance to breakdown before spring seed sowing
- Erect supports for peas and beans; make sure they are strong enough to withstand high winds
- Last chance to carry out winter pruning and plant bare root fruit trees and bushes