The weather this September has been unsettled, with cooler temperatures and a mix of rain, strong wind and sunshine. Make the most of the the dry and sunny days as there is plenty to do in September to prepare for next year.  It is also harvesting time for many fruits and vegetables.

Flowers 

Dahlias are at their peak in September and if the weather is mild they’ll carry on blooming for several more weeks. Likewise cosmos, zinnias and Japanese anemones.

However, by late summer many gardens plants are starting to run out of steam. There is still plenty life left in them if you carry out few simple tasks:

• Feed and water plants during sunny spells
• Nip off spent flowers to keep the bloom coming
• Remove brown and ragged leaves
• Address powdery mildew  – a fungal disease  – keep watering and remove debris and overhanging growth to improve air circulation. 
• Stake top heavy dahlias and sunflowers especially when high wind is forecast.

Plant spring-flowering bulbs: September and October are the best times to plant daffodil, crocus and iris bulbs, tulips can wait until November. 

Saw hardy annual: Nigella, Honesty, Flax, Cornflowers, Poppies, Larkspur … Growing hardy annual flowers from seeds is quick and easy. They are able to survive frost, so can be sown outdoors in autumn. They will survive the winter to bring summer colour to your garden or even your plot. Many will attract pollinators.

• Make sure the area to be sown is weed-free.
• Dig over the soil to a spade’s depth, rake it over and firm.
• Plan the area to be sown by sprinkling grit or sand on the soil or score the ground with a cane to mark out sowing areas. Decide what should go where according to height, habit and colour.
• It is important not to sow into a soil that is too rich, since this may encourage leafy growth at the expense of flowers, so avoid using fertiliser.
• Scatter seeds thinly (or sow into drills) and cover lightly with soil or compost.
• Water well with a watering can fitted with a fine rose.

Plant out biennial: foxgloves, hollyhocks, sweet williams, wallflowers, forget-me not … If you have sown some back in midsummer, or you have young plants from self-seeding,  now is the time to plant them into their final positions.

Divide Perennials … dividing spring-flowering perennials this month, will give their roots time to establish before te weather turns cold.

• Dig around the plant and lift from the soil. Knock off excess soil so that the rootball is easier to handle
• Pull apart each section by hand. Discard old or woody growth.
• Replant each section into a planting hole with added co0mpolst in the base. Form in and water well. Keep watering in dry weather.

Leave perennials for wildlife:  when tidying up your borders, resist the urge to cut back dying perennials. Many have seedbeds (sedum and thistles) for birds  and they can provide shelter for insect as well as protecting the soil from winter weather. 

Take cuttings:  It is your last chance to take semi-ripe cuttings of verbena, penstemon, salvia, lavender to increase stocks and beat winter losses.

1. Select shoots and trim to around 5 cm just below a leaf joint.
2. Remove the lower foliage.
3. Insert around the edge of a pot of compost.
4. Keep moist and out of direct sunlight to root.

Fruit and vegetables

Harvest apples: and lay them carefully to avoid bruising into an open shallow trays. Keep them in a cool frost-free and airy environment.

Harvest and store potatoes: dig them up now and keep them for your home-grown roast potatoes on Christmas Day. 

1. Once the stems have withered, lift potatoes carefully with a fork on a dry sunny day.
2. Leave then on the soil surface to dry their skins for few hours.
3. Brush any excess earth (don’t wash them) and pack into paper or hessian bags.
4. Keep your bags in a cool frost-free, dark, dry place. 

Courgettes and aubergines: pick them regularly to encourage the remaining fruits to develops.

Pumpkins: raise them onto a piece of slate or wood to prevent them from rotting.

Winter salads: Sow lam’s lettuce, mizuna, rockets, mustard leaves.

Plant a strawberry bed: September is the perfect time to create a new patch. 

Don’t forget 

• Tidy your pond: not to allow plant debris to build up. Tidy plants, thin out growth and put netting over the surface to prevent leaves from falling in to the water.
• Return houseplants inside preparing them for winter: tidy them up removing yellowing foliage, check for pests and ease back on watering and stop feeding.
• Neaten up borders:  trim back stems that have flowered in early summer. Cut back dead or flopping stems. 
• Protect soils: spread a thick layer of mulch over bare soil to reduce weathering from winter rains. A 7.5cm-thick layer of biodegradable well-rated co post, straw or bark chips around your plants this autumn will deprive weeds of light preventing them from growing.
• Prepare for leaf fall: making a leaf enclosure to create dark, crumbly leaf mould also known as “black gold”.  More on how to make leaf mould and its benefits in the October Tips of the month. 

In a week time it will be July. Midsummer weather will bring plenty more sunshine with long sunny days and balmy evenings. July is a month of plenty in the garden: plenty summer bloom, plenty to grow and harvest and plenty more to do !

Flowers 

During July, some late spring and early summer flowering plants start to look a little bit rough around the edges with fading flowers and flopping stems. This month is all about tidying and revamping your pots and borders, especially after the very dry and hot weather we had over the last 2 months. Weekly deadheading and feeding will help to maintain healthy growth and encourage more flowers. Also cutting certain perennials back in early July, will reward you with fresh new growth and maybe a second flush of late flowers.

• Cut lavender for drying

A great way to keep shrubs neat and compact. Choosing flowers just as they mature, when they are the most fragrant. The best time is late morning – after the dew has dried but before the sun draws out the essential oil. Hang bunches upside down in a well-ventilated, warm dark spot.

• Care for sweet peas

1. Pick often
2. Water regularly: they are thirsty plants so check the soil at the base to see if they need water.
3. Feed regularly: every 10-14 days with tomato fertiliser, seaweed or homemade liquid comfrey. 

• Provide extra support for dahlias

Heavy rain and gusty winds can be disastrous for dahlias. Add extra support and stakes if summer storms and strong winds are forecasted. Place bamboo canes around the plants with twine around them to hold them in place.

• Prune and tidy summer shrubs

July is the time to prune back early-flowering shrubs, wisteria, philadelphus, weigela. It will allow next year’s flowering wood to develop.

• Harvest cut flowers 

Early mornings or evenings are the best time when the stems are full of water and less likely to wilt.

• Collect and store seeds 

From ripe seed-heads from aquilegias, nigellas, poppies. Ensure that your seeds are dry before storing them in paper envelopes in a dark, cool and dry location.

• Begin sowing next year’s flowers 

Make a head start by sowing pots and trays of early-flowering perennials and biennials. This will give them time to germinate and become substantial plants before winter. Try aquilegia, scabiosa, echinacea, delphinium, lupin, sweet williams, foxgloves. Transplant the seedlings when large enough to handle, avoiding hot weather and opting for cooler days or early morning/late afternoon hours.

Fruit and veg

• Water thirsty plants such as celery, beans, peas courgettes, pumpkins and tomatoes regularly during dry weather. Water only in the early morning or evening to reduce evaporation.
• Make the last pickings of rhubarb and and leave the stems in place; this will allow the plant to build up reserves for next year. Remove any flower spikes that start to form, cutting right down at the base. 
• Thin out heavy crops of apples, pears and plums by removing malformed, damaged or undersized fruits.
• Sow a last batch of beetroots, peas and dwarf beans  before mid-July for an autumn crop.
• Sow veg to harvest during the winter months. Kale, winter cabbage spinach, radicchio, carrots.
• Sow small batches of fast-maturing salad leaves and radishes every few weeks for continuous pickings.
• Cover brassica with fine netting to prevent cabbage white butterflies laying their eggs on the leaves.
• Continue pinching out any side shoots growing from the leaf joints of cordon tomatoes, also known as vine tomatoes. This will encourage the plants to put their energies into producing flowers and therefore fruits. 
• Peg down strawberry runners into pots of compost to root new plants.

Tackle summer pests and diseases 

Pests and diseases can thrive in warm weather. 

• Keep watch for pests such as lily beetles, snails, aphids and vine weevils and remove before they do too much harm.
• Look out for clematis wilt. Symptoms are wilting leaves and black discolouration on the leaves and the stem. Cut out all affected material and dispose of it in your household waste. 
• Stop rust damaging hollyhocks by pruning out affected leaves and dispose of them in your household waste.
• Watch out for blight. In warm damp weather check for dark edges on the leaves of potatoes and tomatoes. Cut out affected leaves and dispose of it in your household waste.

Don’t forget 

• Clear weeds regularly around your crops as they can deprive your plants of water, nutrients and light.
• Continue slug hunting.
• Mulch with compost: a thick layer of well rooted compost, grass clippings or chipped bark around plants, will reduce moisture loss from soil.
• Deadhead flowering plants (unless you want to keep and store seeds): to ensure the plant keeps producing more flowers rather than putting its energy into forming seeds.
• Cool down the greenhouse:  In hot weather,  temperatures inside can rise to extremes, causing plants to become stressed and to dry out. Make sure that vents are open on sunny days. Drape shade nettings over the outside of the greenhouse. Damp down in the morning, wetting hard surfaces inside the greenhouse (floor and shelves) to help plants cope with the heat.
• Prevent powdery mildew.  This fungal disease tends to affect plants in dry spells. Give plenty of moisture in summer and mulch after watering with a compost layer. 
• Prune wisteria. Cut whip stems back to five or six leaves after flowering for healthy growth and to control the overall size. Don’t cut the woody framework. 
• Continue to tie and train new growth on climbing plants.
• Top up birds baths : providing a source of water for birds is crucial in summer, for drinking and feather cleaning.

With the weather getting warmer and the risk of frost having passed, there is a lot that can be planted in both the flower and vegetable garden in April and May. 

Weather watch:

Although the risk of frost is diminishing, it is still a possibility as warm, cloudless days can be followed by cold nights. Keep an eye on the forecast and don’t be tempted to plant out tender plants until the first weeks in May.

Toughen up tender plants 

Seedlings nurtured indoors cannot be planted outside straight away. Instead toughen them up by placing them outside in a sheltered spot for a few hours during the day then bring them inside. Gradually increase the amount of time they spend outdoors . Do this for a period of one or two weeks before planting directly into the ground. 

Divide Primroses

These spring plants can become congested over time . To reinvigorate them  and keep them producing blooms in future years, divide after they finished flowering:

1. Dig them up: choose a cool day when the ground is moist
2. Separate the plants: Using a spade pull apart the clump or slice into sections.
3. Replant your divisions: backfilling the planting hole with compost or leaf mould. 
4. Water well. 

Prune spring-flowering shrubs 

Flowering shrubs such as forsythia, ornamental currants, viburnums, chaenomeles (flowering quince) need to be pruned straight after flowering towards the end of May, so there is plenty of time for new growth to develop and produce flowers next spring. 

1. Use sharp, clean secateurs or loppers for thicker stems and remove any dead or damaged growth to a healthy bud or to the base of the stem.
2. Prune out any stem growing in the wrong direction and spoiling the shape of the plant
3. If the shrub is very congested, thin out the stems by removing a couple from the centre of the plant right down to the base. 

Plant out summer bedding and sweet peas 

Towards the end of May, plant out begonias, tender salvias, pelargoniums, lobelias, sweet peas… Acclimatise plants to outdoor conditions  by putting them outside during the day and bringing them in at night for a week or two. Put the necessary support in place for climbing and trailing. 

Plant up baskets and window boxes with tender plug plants 

For long lasting summer colours it’s the right time to plant up hanging baskets and pots. If it becomes too cold for these plants to stay outside, keep your baskets and containers in a porch or greenhouse for a couple of weeks. 

Sow beans 

1. Sow dwarf, French and runner beans:  5 cm deep into deep pots of peat-free compost and germinate on a sunny windowsill. 
2. Set up supports ready for climbing types:  simply place three to four bamboo canes into the ground and tie to gather at the top. 
3. Plant the beans outside once they have established, from late May. 

Earth up potatoes

Once the stems are 20cm tall, draw soil up to form a ridge along the row. 

This protect shoots from frosty and excludes light, which turns potatoes green and inedible.

Grow salads

Ensure a continuous supply of fresh leaves by sowing a small amount of seed every two to three weeks. 

Plan for a winter harvest

Sow slower-growing vegetables such as cabbages, broccoli and kale for harvesting in winter. Sow seeds in module tray or seedbed for transplanting to final position later. 

Don’t forget 

• Keep on top of weeds: regularly hoe off or pull out annual weeds to prevent them establishing  and setting seeds.
• Get slug hunting: watch plants closely for signs of slug damage.
• Train climbers: tie in soft new shoots of climbing clematis and honeysuckle to their support. 
• Apply a mulch:  to retain moisture: late spring is the perfect time to apply mulch. Adding a 5-7cm layer will help to retain moisture before drier summer conditions arrive.
• Set up plant supports: put plant support in place before perennials get too big.
• Water wisely during dry spells: focus watering on newly planted specimens. Do your watering in the early morning or early evening to minimise water loss from evaporation.