Gardeners’ World 2021 episode 10

Gardeners’ World 2021 episode 10

Gardeners’ World 2021 episode 10: At Longmeadow, Monty adds flowers for pollinators to his wildlife garden, creates an alpine trough and plants out tender veg in his vegetable garden.



Adam Frost uses the wonders of technology when comedian Susan Calman contacts him for advice with her garden in Glasgow, and we travel to Devon to visit an enthusiast who has discovered a passion for collecting different varieties of a highly scented spring-flowering shrub.

Nick Bailey shows us how we can all attract wildlife into our gardens by making a simple a pond in a barrel, and we explore some new ideas of planting in the Sheffield garden of Professor James Hitchmough.


Gardeners’ World 2021 episode 10


Greening balconies and roof gardens

If you live in a building without its own garden, gardening on a roof or balcony is the ideal way to create your own mini horticultural haven. There are a few challenges to growing in these environments, but the rewards are huge. Great views, wellbeing benefits, increased insulation for the building below and the chance to make a wildlife habitat are just some of the reasons why gardening in the sky is a great idea.

There are many strategies to reduce the weight of your garden. Try fibreglass, plastic or lightweight metal containers – these also have the advantage of being non-porous so the soil inside them won’t dry out as fast as in terracotta pots. Add polystyrene in the bottom of pots to aid drainage and reduce weight compared to the traditional crocs. Be aware that different composts weigh different amounts: soil (loam)-based composts like John Innes No.3 are good for long-term plantings, and they don’t dry out as quickly as soilless (multipurpose, peat-substitute) ones, but they are heavier.

One way of getting around weight issues is to install a ‘false floor’ such as decking which is partly or completely suspended above the existing roof, directing weight onto surrounding walls. Or you can place any heavy containers near load-bearing walls or over a load-bearing beam or joist as these can take more weight than unsupported areas.

Grow your own chillies

Sweet peppers and chillies can be grown in pots on a sunny, warm patio in a similar way to tomatoes, but will produce a better crop when grown in a greenhouse or conservatory. Chillies and peppers are green when young, maturing to a variety of colours and flavour varying from mild to extremely hot.

Peppers and chillies need a warm, sunny sheltered position and, therefore, are only suitable for outdoor cultivation in milder parts of the country, and benefit greatly from cloche or even fleece protection. They can be grown in frames, unheated polythene tunnels or greenhouses and are also suitable for growing in containers or grow bags filled with multipurpose compost.

They require well-drained and fertile, moisture-retentive soil, which is slightly acid. To achieve this, incorporate moderate amounts of well-rotted manure (5.4kg per sq m/10lb per sq yd) into the soil, but avoid using fresh manure or large quantities, as this may lead to lush, leafy growth at the expense of fruit.

Soil types – Gardeners’ World 2021 episode 10

Knowing whether your soil type is clay, sand, silt, loam, peat or chalk will help you choose the right plants for your garden and maintain them in good health.

Clay soils

Clay soils are rich in nutrients and very fertile if their cloddiness can be broken up by the addition of organic matter. This breaks down the clay into separate crumbs, making the water and nutrients held within the clay more easily available to plant roots. Breaking up the clay into crumbs also makes the soil warmer, more easily workable and less prone to compaction.

Sandy soils

These light soils are usually low in nutrients, and lose water very quickly being particularly free-draining. You can boost the water and nutrient holding capacity of your soil by adding plenty of organic matter to bind the loose sand into more fertile crumbs. Fertilisers may also be necessary to give plants grown in sandy soils an extra boost.

Silt soils

These soils are made up of fine particles that can be easily compacted by treading and use of garden machinery. They are prone to washing away and wind erosion if left exposed to the elements without plant cover. However, they contain more nutrients than sandy soils and hold more water, so tend to be quite fertile. You can bind the silt particles into more stable crumbs by the addition of organic matter.


These soils are the gardener’s best friend, being a ‘perfect’ balance of all soil particle types. But even though they are very good soils, it is important to regularly add organic matter, especially if you are digging or cultivating these soils every year.

Chalky soils

Chalky soils are alkaline, so will not support ericaceous plants that need acid soil conditions. Very chalky soils may contain lumps of visible chalky white stone. Such soils cannot be acidified, and it is better to choose plants that will thrive in alkaline conditions. Many chalky soils are shallow, free-draining and low in fertility, but variations exist, and where there is clay present, nutrient levels may be higher and the water holding capacity greater.

How to make a raised bed

Raised beds are great for growing vegetables, fruit and flowers and are especially useful if your soil is wet or poorly-drained. They’re also handy for gardeners with bad backs. Dig out strips of turf wide enough to accommodate the timbers. Pressure-treated softwood sleepers are an economical alternative to hardwoods like oak.

Lay the timbers out in position and check that they are level using a spirit level. Check the levels diagonally between timbers as well as along their length. Ensure the corners are at right angles by checking the diagonals are equal in length. For a perfect rectangular or square bed, it’s worth having the timbers pre-cut to size when you buy them. Using a rubber mallet, tap the wood so that it butts up against the adjacent piece; it should stand perfectly level and upright according to the readings on your spirit level.

Drill through the end timbers into the adjacent pieces at both the top and bottom to accommodate a couple of long, heavy-duty coach screws. Screw firmly into position, securing the base ready for the next level to be built. Arrange the next set of timbers, making sure these overlap the joints below to give the structure extra strength. Check with a spirit level before screwing in the final set of fixings, as for step 5.

If you want to grow plants that love good drainage (such as alpines), fill the base with builders’ rubble or chippings. Fill the bed up nearly to the top with topsoil and compost.


Blackcurrants are easy to grow producing sharp but delicious fruit with distinct flavour that are rich in vitamin C. The flowers are insignificant but attractive to pollinating insects and the foliage is pleasantly aromatic.

Ideally choose a sunny position sheltered from cold winds and late frosts that can damage the flowers in spring, though modern cultivars show better cold resistance. Blackcurrants can be grown in light shade. Blackcurrants will tolerate a wide range of soils, but being heavy feeders they prefer moisture-retentive fertile soils that are reasonably well-drained. They can cope with slightly impaired drainage.

Remove all perennial weeds, then incorporate into the planting area 5cm (2in) dressing of bulky organic material, such as manure based soil conditioner or garden compost. This is particularly important on light soils. Just before planting, fork in a compound fertiliser such as Growmore at 85g per m² (3oz per sq yd). Buy two-year-old bushes container grown or bare-root FPCS certified stock (The Fruit Propagation Certification Scheme).

Plant bare root plants between October and March, but it is generally best to avoid planting in the middle of winter when the soil is either wet or frozen. Container-grown plants can be planted almost any time, but need regular watering during the dry periods. Plant both container-grown and bare-root bush plants 5cm (2in) deeper than previously planted; look for the nursery soil mark at base. This will encourage strong shoot development from the base. Plant standards at the same soil depth as previously grown. Space plants 1.5-1.8m (5-6ft) apart, using the wider spacing for vigorous cultivars.

How to grow agapanthus – Gardeners’ World 2021 episode 10

These dramatic sun-loving border plants produce large spherical flowerheads, usually in beautiful shades of blue, from midsummer onwards. These sway on tall stems above clumps of strappy foliage. Some types, especially the evergreens, may not be fully hardy, so are best grown in containers that can be protected from frost over winter

Grow all agapanthus in well-drained soil in full sun. Avoid planting in shade as they won’t flower much.

In borders

In the border, ideally plant your agapanthus in spring. If they are growing in containers, plant them the same depth that they are in the pot. If you have bought bulbs or fleshy rhizomes , the noses should be covered with 5cm (2in) of soil. ​If your soil is prone to waterlogging, or you live in a cold area, grow agapanthus in containers.

In containers

Grow single plants in 20-23cm (8-9in) in diameter containers using a loam-based compost, such as John Innes No. 2 or No. 3. All container plants (hardy or tender) benefit from some winter protection (see Overwintering below).


Tulips are amongst the most popular of bulbs, valued for their brilliant flower colours and shapes. Plant in autumn for a show of spring flowers. Choose from a large range to suit the situation.

Gardeners’ World 2021 episode 10 (1)
Gardeners’ World 2021 episode 10

Whether used in formal or informal beds and borders, tulips make ideal bedding plants combined with annual or biennial planting. Tulips can also be useful for containers, and some varieties can be naturalised in grass. Tulips grow best in fertile, well-drained soil in full sun, sheltered from strong winds. All dislike excessively wet conditions; this is particularly true with alpine species which require excellent drainage. Exceptions include Tulipa sprengeri, T. sylvestris and T. tarda which prefer a more moisture-retentive soil with partial shade.

Incorporate organic matter into the soil before planting to improve both clay and sandy soils, making them much more suitable for tulips. Coarse gravel can also help improve growing in clay soils. Apply Growmore or chicken manure pellets (70g per sq m or 2oz per sq yd) before planting to help nutrient-poor soils. A neutral to alkaline soil is preferred. Soils with a pH lower than 6.5 may need applications of lime.

2 thoughts on “Gardeners’ World 2021 episode 10”

  1. Nick Bailey made a small pond in a barrel, he added a “powder dye” to the water, to keep it clean. What is the name of this product ?

  2. Pingback: Gardeners’ World 2021 episode 11 — HDclump — Gardeners’ World 2021

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