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Growing Herb Plants

Growing Herb Plants

Most herb plants are easy to grow if you can give them suitable growing conditions.

Generally the Mediterranean herbs (including thyme, marjoram, rosemary, sage) need well drained, poor soil, lots of sun, and they don’t mind being dry for a while (once plants are established).

Mint requires rich soil (and will need to be split and replanted in fresh compost every so often), plenty of water and good light, but will not like being in strong midday sun.

Growing mint as a garden plant

Mint is very easy to grow. However there are a few important things to remember.

Grow mint in pots

It is best to grow mint plants in a large pot, rather than plant into the garden – mints can be rampant spreaders.

Mints spread by creeping rhizomes, and can get out of control very quickly.

Don’t plant different mints in the same pot

Some mints (like spearmint) are real thugs and will out-compete other more delicate mints.

Mint plants also seem to lose their unique flavours and fragrance if they are grown too close to different mint varieties.

Water mint well

Give mint plants plenty of water, especially in warm weather.

They are thirsty, hungry plants.

Bright – but cool – site

Mints like good light but will usually prefer a cooler site which gives some protection from excessive heat and strong midday sun.

They will not be happy on a hot, south-facing patio. (Save that location for dry sun lovers like thyme and rosemary.)

Cut regularly

Regularly cut the stems and use for tea or cooking (or to make new plants – see propagating mint, below). As with most herb plants, this will promote fresh growth – which tastes better – and delay it from flowering.

Annual care

Mint plants die back in the winter, and will usually start to grow new leaves in March/April.

Cut back any old dead stems. Rejuvenate old plants by pulling the plant apart, trimming off excess root and runners, then replanting the best plant sections into new compost. Water well and within a few days the plant should be growing again, and will be much stronger and healthier.

Flowering

Regular stem cutting will delay flowering. If your mint flowers, but you want to make it productive again, cut it back hard and give it some food. It should start to grow again in a few weeks.

Pests and problems

Aphids
Aphids are a particular problem at the start of the growing season in spring. Aphids love the young juicy growing shoots as the new growth begins to appear. Weak or stressed plants are usually worst affected.

  • Snip off the affected stems (this will also encourage the plant to bush out with new growth).
  • Keep the plant well watered, and keep it out of strong hot sun.
  • If you haven’t re-potted the plant since last year, divide up the plant and re-pot the best sections into fresh compost in a large pot (a sprinkle of slow release plant food and some water retaining gel will be beneficial).

Caterpillars
After the aphids go away – the caterpillars arrive.
Look out for leaves with holes or leaves which are curled up or stuck together (look between the stuck leaves and you may find a tiny caterpillar hiding there).

  • Remove affected leaves.
  • Check the plants every day or two so that you can hopefully remove caterpillars before they cause too much damage.

Growing Thyme, Sage and other Mediterranean Herbs

Thyme, Sage, Margoram and Rosemary are Mediterranean herbs which typically grow in hot dry areas in poor soil. These herbs will be happy in full sun, and will prefer to be planted in well drained gritty soil, and in poor soil which is not high in nutrients.

Picking herbs to dry

It is possible to pick herbs such as thyme or marjoram and dry them for use later in the year. The best time to do this is just before the plant flowers. Most herbs have their best flavour just before they flower. Once the flower buds appear the plant changes behaviour, producing less leaves and more flowers.

Pick the best young stems (either with no flowers or with just small buds). Pick on a warm sunny day and thinly spread the stems out on a large tray in the sun to dry (a hot conservatory or sun room is great for this.
Once fully dried (usually a couple of days), rub the leaves away from the stems and store them in a suitable airtight jar.