In your herb garden in May 2013
As our gardens slowly start to warm up after the long winter chill, perennial herbs begin to put on growth again. Soon we’ll be able to indulge in our favourite flavours and scents once more.
There are still plenty of tasks to keep us busy, despite the slow start. Don’t let weeds sprout and seed, make sure that early pests are dealt with rapidly, and keep sowing annual herb seeds. Above all, enjoy the beautiful month of May.
Rosemary - great to look at, delicious to eat and a brilliant bee-attractant
Things to do in the herb garden this month
- Grow herbs for your bees. These wonderful plants are perfect feeding stations for our bees, which we know are having a difficult time. When in flower, herbs like thyme, rosemary, marjoram, will be covered in feeding bees. You’ll hear the humming! Give our bees a chance! Grow the plants they love!
- Seeds sown outside earlier in the year may well have failed due to the adverse weather. Re-sow where there is absolutely no sign of germination. You can always thin out later if necessary.
- Continue to sow seed under cover. Basil germinates beautifully on a warm sunny windowsill.
Basil seedlings need sunshine
Reflect light to the back of seedlings
- Seeds growing in pots on windowsills tend to lean towards the light. Fix a reflective screen at the back of the pots, facing the window. This will light up the shady side and the plants will grow straight . Foil covered cardboard is easy to assemble and easy to fix. See below for ideas on what to sow.
- Prick out and thin any seedlings that have managed to germinate from last month’s sowing. This will encourage vigorous growth and strong plants to develop.
- Hoe and remove weeds as they appear. Don’t let anything seed. Chickweed will produce 2000 seeds per plant per season if left untouched.
- In the middle of the month, start to harden-off any half-hardy plants that have been raised indoors, or under glass. This can be a tedious task, but it’s essential to get these young tender plants used to outside conditions before they’re planted in the open. The following schedule should always be weather permitting.
- Days 1 – 5. Take plants out of the greenhouse during daytime only, (and only if the weather is reasonable), and return late afternoon. In bad weather (cold winds, heavy rain), leave plants in the greenhouse, but open the door halfway. Or, if growing on windowsills indoors, take plants outside, but cover with fleece.
- Days 6 – 10. Take plants out during the day, return early evening, and leave the greenhouse door ajar overnight.
- Days 10 – 15. Take plants out and leave out overnight, but cover with fleece.
- Days 16 onwards. Leave plants outside, but be ready to cover with fleece should the weather turn cold.
- At the end of the month, plants should be ready to plant out. But watch out for late frosts. If in doubt, cover plants with fleece, and wait a little longer.
- If you have a cold frame, plants can be left there, and the frame opened as the above timings.
- Plant out hardy herbs such as foxglove, sage, yarrow and violets that have been grown in containers and pots.
- Cut back shrubby herbs such as southernwood (Artemisia abrotanum), myrtle (Myrtus spp), cotton lavender (Santolina chamaecyparissus), bay (Laurus nobilis) and rue (Ruta graveolens), to encourage new growth and side-shoots, and to maintain an attractive shape. Use the trimmings for cuttings.
- Take softwood cuttings. New growth of lavender, lemon balm, lemon verbena, oregano, rosemary, santolina, sages, thymes, and scented pelargoniums make perfect softwood cuttings at this time of year.
- How do I take softwood cuttings?
Bergamot in flower
- If your lavender (Lavandula spp) was not cut back after flowering last summer, cut back now. Don’t cut into old woody stems; new growth is unlikely, and you’ll end up with a miserable looking plant doing very little. Discard old plants and start again with fresh young stock. Prune after flowering, annually..
- When buying new lavender plants, make sure they are all the same variety. Heights can differ, and you’ll end up with an irregular border.
- There is still time to divide creeping thymes, verbena (Verbena officinalis), valerian (Valeriana officinalis) and bergamot (Monarda spp.).
- Divide mint if it has become too large. This is an invasive plant so make sure you get all the roots out. In a small garden, grow mint in pots. It does very well in a restricted space
Mint grows well in pots
- Cut woodruff flowers when out, for drying
- Cut thyme for drying before it flowers. If possible, leave some plants to flower as bees love thyme and will feed happily on the nectar. See the information below about how to dry herbs.
- Top dress perennial herbs growing in containers. Scrape off the top 4cm/2” of compost, and replace with fresh potting compost or garden compost.
- In dry spells, water plants growing in containers. Mulch the top surface with gravel, or leaves, to retain moisture.
- Despite last year’s continuous rain, a drought is always possible. It makes sense to save water whenever you can. Water used for scrubbing potatoes, washing salad, even rinsing fingers, can all be saved and used on the herb garden. Have a bowl or bucket to hand to catch any semi-clean water. Check out Garden Organic’s Top Ten Tips for water saving.
- Keep some fleece ready for frost protection. In May high daytime temperatures can turn into a cold night as the sky is so clear. Young plants will appreciate some light cover to protect new soft growth.
Starting a herb garden for the first time?
One of the easiest ways to start growing herbs is to buy a collection of plants. The Organic Gardening Catalogue has just the thing. They are all organically grown, which is nice to know.
- In general herbs prefer a well-drained soil, so if you’ve got heavy clay or solid silt, improve drainage by digging in coarse horticultural grit before planting. Add bulky organic material, such as last year’s semi-rotted leaves, whenever you can. This will open up heavy soil and create a good growing environment.
Another solution is to set up a bed system, surrounded by easy access paths. Never stand on the growing area, always work from the sides, and you’ll have an ideal plot for your herbs.
An ornamental herb garden
- Don’t overfeed herbs. Many do best in impoverished soil and excessive nutrients just result in soft growth susceptible to pest and disease attack.
Flavour from the garden this month
- Angelica (Angelica archangelica)
An attractive, hardy biennial/short lived perennial. Produces sweet-scented, greenish-white flowers in late spring/early summer of its second year. The leaves can be added to rhubarb dishes to cut through the acidity and the stems can be candied.
Cut young, tender springtime shoots of angelica into 8-10cm lengths. Simmer in just enough water to cover them until they are tender, then peel off the outside skin. Bring back to the boil, then strain and allow to cool. Weigh the angelica stalks and place them in a covered dish with an equal weight of granulated sugar. Leave in a cool place for 2 days. The sugar will turn into syrup. Put this and the stalks into a pan and slowly bring to the boil, stirring occasionally. When the angelica is translucent and has good colour, discard the liquid, then cover the stalks with as much caster sugar as will stick to them. Dry the stems in a cool oven and store in an airtight container.
- Caraway (Carum carvi)
Hardy biennial herb, which produces tiny white flowers in its second year. Use young, aniseed-flavoured leaves, produced during its first year, in salads. Harvest seeds in the late summer of the second year to use in breads and cakes.
- Pennyroyal (Mentha pulegium)
Hardy, semi-evergreen perennial herb with small, oval, highly-scented leaves. Dried pennyroyal can be sown into sachets and hung amongst clothes to repel moths.
- Lemon balm (Melissa officinalis)
Hardy perennial herb with highly-scented leaves. The small, cream flowers produced in summer have a light lemon scent and sweet flavour. It makes a lovely soporific tea.
- Rosemary (Rosmarinus officinalis)
Hardy evergreen shrub. The ever-popular rosemary, used to flavour so many dishes year-round. It is also adored by bees, who feed greedily from its flowers, then go on to produce delicious honey. Sturdy stems can be used as skewers at barbecue time. Add sprigs of rosemary to the pan as you roast vegetables. Cuttings root easily at this time of year. It is a drought survivor, and grows well in large pots. It also makes a stunning informal hedge.
- Bergamot (Monarda spp.)
There are many species and cultivars of bergamot, but they are all hardy perennial herbs with aromatic leaves. The scent is similar to bergamot orange (Citrus bergamia), which gives the plant its common name. The leaves can be used to make a herbal tea, or in wine cups and lemonade. The flowers can be added to salads for colour and flavour, or dried and used in pot pourri.
Borage and Viola
- Borage (Borago officinalis)
Hardy annual, producing blue, star-shaped flowers from early summer until the first frosts. Fresh leaves can be added to salads and soups. Bees love the flowers, which can be added to salads or crystallised for cake decorations. The flowers also look great when frozen in ice cubes for summer drinks.
How to Crystallise Flowers and Leaves
Crystallised flowers and leaves make lovely decorations for desserts, cakes and summer drinks and punches. Making your own is very simple:
- Pick leaves or flowers on a dry, sunny day.
- Remove stalks.
- Lightly beat an egg white, until it is foamy.
- Dip each leaf or flower into the egg white to coat, then dip into caster sugar.
- Place on a sheet of greaseproof paper and cover lightly with another sheet.
- Place in a dry airing cupboard or very low oven with the door left ajar.
- When completely dry store in an airtight container.
Leaves to crystallise
- Bergamot, lemon balm, lemon verbena, mints
Flowers to crystallise
- Borage, rose, rosemary, sage
Herbs to propagate this month
- Basil (Ocimum basilicum) Annual
Sow into pots or plugs as basil does not like to be transplanted. Sow indoors or under glass (minimum temperature 13°C). Basil adores hot sunny locations so a south facing windowsill usually results in good germination. Plant out only when all threat of frost has passed. When grown indoors on a sunny windowsill, or kept in the greenhouse, basil plants have softer, larger leaves.When searching the Organic Gardening Catalogue, the tasty basil selection includes organic seed for 'Lemon', 'Lettuce Leaved' (one of the most productive), 'Red Ruben', ‘Greek’ and 'Cinnamon'.
- Coriander (Coriandrum sativum) Annual
Sow directly into well-drained soil in a sunny position, when night temperatures are above 7°C. Do not transplant this herb, as this will cause it to bolt. For leaf production, sow every few weeks, because it quickly runs to seed. Thin seedlings to 5cm intervals for a leaf crop; 25cm for a seed crop.
- Chervil (Anthriscus cerefolium) Annual
Once night time temperatures are above 7°C direct sow at three to four weekly intervals in rich, light, moisture retentive soil. Thin to 20cm apart. Prefers partial shade and will bolt in high temperatures or in dry, sunny positions.Organic chervil seed is available from the Organic Gardening Catalogue
- Dill (Anethum graveolens) Annual
Sow into well-drained, neutral or slightly acid soil in a sunny spot. Thin to 20cm apart. Dill will bolt if sown into poor, dry soil; or if overcrowded.Organic dill seed is available from the Organic Gardening Catalogue
- Lady's mantle (Alchemilla mollis) Perennial
Sow seed in a prepared seedbed in normal garden soil, or in seed trays with a general seed sowing compost. Germination can be erratic. Lady’s mantle will tolerate sun and partial shade, but not very wet soils.
- Pot Marigold (Calendula officinalis) Annual
Sow in situ in an area of full sun. Will grow in most soils, except poorly drained, waterlogged soils. It is very vulnerable to slugs so set traps, or use barriers. All available from The Organic Gardening Catalogue.
- Sweet marjoram (Origanum marjorana) Annual, half-hardy perennial
Sow seed in pots or trays in April - May. Seed is very fine, so try sowing with small amount of silver sand or sieved potting compost. Leave uncovered. When large enough to handle, pot on or plant out in a warm, sunny area. Sweet marjoram is grown as an annual in cooler climates, as it tends to die in cold, wet winters. Can be potted up and overwintered in a cold greenhouse.
- Nasturtium (Tropaeolum spp.)
Sow direct or in pots and transplant to prepared site after last frost. If growing for flowers, place in nutrient-deficient soil, if growing for spicy leaves, grow in rich soil. Makes a great groundcover plant under hedges.
- Wild or perennial rocket (Diplotaxis tenuifolia).
Unlike annual rocket, this variety will not bolt and become bitter. Even in flower the leaves remain edible. Flavour is usually pungent and peppery. Leaves are produced all summer, and well into winter if the plants are covered with cloches or fleece. It can be cut back hard and will bounce back readily. It grows well in pots.
Cutting ready for planting
Rooted cuttings with new
All sorts of shrubs will be producing fresh growth now, perfect for propagation.
- Remove young, non-flowering shoots and, using a clean, sharp knife, remove the growing tips.
- Remove the lower leaves, leaving just a few leaves at the top of the cutting. Cut the stem just below a leaf node.
- Use a dibber or pencil to insert the cuttings into modules or pots of free draining compost.
- Keep pots in a shady part of the greenhouse, or on a north facing windowsill, until rooted (usually about 8 weeks).
How to dry herbs
- Herbs can be dried in the air, in an oven, or in the microwave.
- Air drying:
- Hang the fresh herbs upside-down in bunches in a dark, dry, airy place. Keep the bunches 'loose' so that moisture can escape.
- Hang paper bags over the herbs (use pegs) to make sure that none fall on the floor.
- Leave them until they become dry and can be crumbled easily.
- Drying in the oven:
- Set the oven on the lowest possible heat. 30C is ideal, but not all ovens will do this.
- Spread the clean herbs out on a baking tray or drying rack and put them in the oven for several hours.
- Keep checking them and repeating the process until the herbs are completely dry and will crumble.
- Drying in the microwave:
- Spread the herbs on a bed of kitchen towel.
- Run the microwave on high for 1 minute, then check the herbs.
- Repeat until the herbs are dry. You may need several goes as this method is slightly tricky. Don’t expect perfect results at first. And don’t put all the herbs in at once, just in case.
- After the herbs have been dried, store them in dark containers in a cool place.
Many herbs seem fairly pest-resistant. However there are always exceptions!
- Soft, lush basil leaves are often targeted by slugs and snails when first planted out. The Organic Gardening Catalogue has a wide range of controls to use against these pesky munchers. Try the slug nematode once the soil is warm enough, use copper collars round pots, and slug-stoppa granules round plants in the ground. Don’t rely on just one method. Usually, once plants are large enough, they will survive.
- Basil grown indoors can also be infested with greenfly. They blow in through open windows in warm weather. Use an insecticidal soap spray, but wash leaves well before using for food.
Alternatively, place plants outside in the sun, and wait for ladybirds to come and mop up the aphids!
- Mint rust will carry over from one season to the other. Spores survive in the soil overwinter and re-infect plants in spring. Look for tell-tale signs, yellow/orange pustules on leaves. Remove contaminated plants, and replace with fresh stock. Marjoram and savory can also be infected with this same disease.
- Rosemary beetle can be a problem on lavender, sage and thyme as well as rosemary. Check the underside of leaves for soft-bodied larvae, greyish white, with five dark lines running from head to tail. Pick off and dispose of when found