What to do in your garden in January
January marks mid-summer in the garden and the weather can be very unpredictable; it can be terribly hot and dry; or extremely wet. There is a lot to be done in the garden this month; in regions that have received heavy rains it is essential to feed regularly, as heavy rains leach food out of the soil. In very hot and dry regions do not overfeed, especially with high nitrogen feeders, as this will encourage lush, soft growth that is easily scorched. In hot regions try to do your gardening chores in the early morning or in the late afternoon. Do not transplant shrubs this month and plant seedlings in the cool of the evening. To keep your bedding plants flowering into autumn, continue to feed them and cut out the dead flowers regularly; it is also time to start sowing many winter flowering annuals and vegetables.
Before planting that cute little Christmas tree you bought into the garden, please find out how big it grows first. Most varieties are very large growing and will eventually dwarf small gardens, producing dense shade and allowing nothing to grow underneath them. Rather consider re-potting your tree into a larger container and growing it on for next year. Place the pot in a semi-shaded position for a few weeks, so that it can acclimatise to the outdoors, before moving it into direct sun.
Preventative spraying of roses is the best control method for pests and diseases; during wet weather the plants are susceptible to black spot, and in hot dry weather they can be plagued by red spiders, so keep a look out for these. Continue to fertilise regularly and prune lightly if necessary to remove any weak or spindly growth; but remember that roses need plenty of healthy leaves to protect them from the fierce summer sun.
azaleas, camellias, hydrangeasand fuchsias need plenty of water during hot, dry spells and will benefit from having their leaves sprayed down regularly with water. Your camellias will be forming their winter and spring buds now, so water them regularly but don’t over fertilise them now as this may cause them to abort their flower buds in favour of new leaf growth. Remove any seeds from your fuchsia plants and pinch back the growing tips that are not flowering, this will encourage the formation of secondary buds along the stems; feed with organic 3:1:5. Remove faded flowers from your hydrangeas unless you want to keep them for autumn colour. Cut them back to the first pair of healthy, plump looking buds; and tidy them up by cutting old woody stems out completely at the base of the plant. This will encourage new basal growth.Water loving plants like
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Do not cut your lawn too short, keep it at a height of 5cm, and remove any grass cuttings immediately. Fertilise regularly with a balanced, organic fertiliser. A fertiliser high in potassium like 3:1:5 or 5:1:5 will encourage strong, deep roots that are more heat tolerant.
If necessary, mulch your beds with a layer of compost or bark chips, to conserve moisture. Do not mulch with wood shavings, as this will attract white ants. Coarse bark mulch, bought from a reputable supplier contains a type of tannin, which repels white ants.
Shasta daisies, lavender anddaisy bushes when they have finished blooming in order to promote a second flush of flowers before winter. If you are planting potted chrysanthemums into the garden, first pinch out the growing tips to encourage bushy growth. Tug out the flowering stems of Inca lilies(Alstroemaria) as they finish flowering and remove the spent flower spikes from your agapanthus. If your wild rhubarb (Acanthus) is untidy cut it right back to ground level, mulch it with compost and water well.Do not split and divide perennials in summer when they are actively growing; rather do this in autumn, or in spring and early summer. Cut back perennials like
Perennials and bulbous plants are wonderful additions to the garden, adding seasonal colour and contrast throughout the year. If carefully worked into the landscape and cared for correctly they never fail to perform and are a delight to have.
Amaryllis belladonna (March lily) as soon as they are available; and they should provide a romantic display of scented pink and white trumpet flowers in time for Valentine’s Day – remember to keep the necks of the bulbs above ground level. Finish planting Nerine bulbs, and collect any ‘plantlets’ on the older stems of your day lilies to propagate. Feed your Liliumsand cut off the spent flower heads regularly, but when cutting leave as many leaves on the plant as possible, as these will produce food for next seasons flowers. Sow Anemone andRanunculus seed before the end of January, so that they will be ready for the winter and spring garden. Cut back the spent flowering stems of Cannas to encourage continuous flower production, and water regularly. Lift and divide overcrowded white and green Arum Lilies that are starting to die down. Cut off all the old leaves and replant only healthy plants, adding lots of compost and a generous sprinkling of bone meal.Plant out bulbs of
lily borer caterpillars, they attack the bulbs and leaves of many plants like amaryllis, agapanthus, crinum, nerine, clivia, and crytanthus. Spray regularly with Margaret Roberts Biological Caterpillar insecticide.Check for
Red spiders are especially troublesome during hot, dry spells and affect many plants, including fuchsias, roses, hydrangeas and beans.
During hot, humid days, or following heavy rainfall, fungal diseases like, powdery and downy mildew, rust and black spot are especially prevalent. Barberton daisies, roses, dahlias, daisy bushes, geraniums, hydrangeas and vegetables like pumpkin, squash, eggplant and tomatoes are very susceptible.
Prune wisteria climbers that are growing rampant but do not remove the new flower buds that are forming near the base of the new branches. These will bloom next season. Lightly prune your bottle brushes when they have finished flowering. Remove all the soft, red-brown water shoots from the base of your bougainvilleas as soon as they appear.
Remove the decaying leaves from your aquatic plants in ponds, as they can pollute the water.
Cymbidium orchids with a feeder that is low in nitrogen but high in potash like 3:1:6 to encourage the formation of flower spikes. Water and mist spray regularly in very dry regions.Start feeding your
Mist spray your indoor pot plants regularly with water, this will keep them clean and healthy, especially in air-conditioned homes and offices where the air tends to be dry. Occasionally, place them outside in a shady spot and hose the leaves down gently with water, or even better, put them outside when it is raining gently.
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Your vegetable garden should be flourishing, so harvest regularly to ensure that your plants keep producing. Carrots should be pulled before their shoulders go green beans before they become ‘stringy’ and baby marrows before they become too large. Lift and divide your shallots, replanting only healthy bulblets; and as your onions mature, reduce the amount of water they receive. When your onions are ready to harvest, lift them with a fork and shake off excess soil before laying them out to dry in a cool, well-ventilated place.
potatoes have finished flowering, reduce watering, and when the leaves go yellow you can test to see if they are ready to lift. To store, brush off the excess dirt and ensure that the potatoes are completely dry before storing in a cool dark place – do now wash before storing. Provide support for heavily the laden branches ofeggplants and tomatoes.Once your
Feed and water your veggies regularly, especially in hot, dry weather; and if sowing seeds directly into garden beds in the heat of summer, remember that they may require watering twice a day; mulching with straw or dry grass cuttings will help to conserve moisture.
Always check your ‘weeks to maturity’ on the back of your seed packets before sowing vegetable crops at this time of the year, or crops which need a long growing season like brinjals, peppers, tomatoes and pumpkins will start maturing too late to be successful. In regions which experience early frosts, plant out only well-established seedlings of these slow maturing crops. Continue sowing fast maturing summer vegetables like baby marrow, radish, spring onions and Swiss chard and plant only heat tolerant varieties of lettuce. January is the last month to sowgreen beans unless you live in subtropical areas.
lettuce like ‘Vera’, a lovely frilly red variety, and ‘Veneza Roxa’, a frilly green lettuce; and ‘Elise,’ a great butter lettuce are all heat and cold tolerant and grow quickly if grown correctly, making them ideal to sow or plant out now. Individual leaves can be harvested as required when the plants are young and the whole plant can be harvested towards the end of the growth cycle; making them perfect for summer salads. Lettuce requires fertile, well-drained soil and grows best in semi shade in summer (30% shade is sufficient). Mulch the plants and water regularly, keeping the soil constantly moist; this prevents them from tasting bitter and running to seed. Water occasionally with 1 teaspoon of Epson salts to 1 litre of water for great leaf colour and taste. Keeping the seeds in the refrigerator overnight before sowing will help germination.Loose leaf varieties of
thyme, oregano, marjoramand rosemary. In frosty regions sow a last crop of annual herbs likeBasil, borage, coriander, dill, rocket, parsley,sage and mustard. Take semi hardwood cuttings of herbs like rosemary, thyme,tarragon, marjoram and sage. Comfrey has the most beautiful flowers and I cannot bring myself to cut them off until the flowers begin to fade; but cutting comfrey back as it comes into bloom will encourage a new batch of leaves. Add the harvested leaves to your compost heap or use them to make a wonderful liquid fertiliser.Continue to plant perennial herbs like
marigolds, vinca, celosia, verbena, alyssum,gazanias and cosmos for sunny areas, and begonias and coleus to brighten up shady areas. Established petunias and salvia can be cut back, mulched and fertilised to encourage more flowers.January is an awkward time of the year to sow flowering annuals, especially in cold winter regions, as many of them will be at their best just when the cold winter weather hits, so check the ‘weeks to flowering’ on the back of your seed packet before sowing. Instant colour seedlings from your nursery may be a better choice at this time of the year; try
In cold winter regions it is time to start sowing winter and spring flowering seedlings such as pansy, cineraria, foxglove, aquilegia,Iceland poppy, viola, delphinium, larkspur and primulas into seedling trays. Keep them moist and in a cool, shaded area. Store larkspur and delphinium seed in the refrigerator before sowing to improve the germination rate.
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Berries like loganberries, youngberries and raspberries need to be fed and the new canes tied onto supports. Harvest your Cape gooseberries regularly and feed your strawberry plants with a high nitrogen fertiliser, water them regularly and mulch the soil.
Grapes are susceptible to downy mildew, so water early in the morning and spray regularly with an organic fungicide. Feed them this month with a fertiliser that is high in nitrogen. As the grapes mature reduce watering; and for the best flavour only harvest them when they are fully ripe. Protect the ripening bunches from birds with mesh bags or bird netting.
If your citrus trees are bearing too many fruits, thin them out and water deeply and regularly, especially in dry regions.
Prune your deciduous fruit trees in the summer by removing any strong branches that are growing in the centre of the top of the tree and overshadowing the centre; or the fruit bearing shoots on the inside of the tree could die off because of a lack of sunlight, and developing fruit that receives too much shade will have a poor quality. When your trees have finished bearing, feed them with a good general fertiliser like 2:3:2 and remove all fallen or rotten fruit from the ground. Continue to splash fruit fly bait onto the leaves of late bearing varieties every ten days. Spray quinces against coddling moth.
Feed tropical fruits like bananas, mangoes and paw-paws with a balanced fertiliser. Feed your avocado trees with an organic 3:1:6, this will help prevent the fruit from dropping prematurely. Feed your bananas with 3:1:6 and keep them moist. You can also feed your paw-paws and mangoes with 3:1:6 or 2:3:2.
Summer rainfall (Temperate or Highveld Regions)
January is one of the hottest months of the year and it can be very windy, with lots of thunderstorms. Rain quickly leaches nutrients out of the soil, so fertilise your beds regularly with a balanced, organic fertiliser.
It is too late to sow most summer seedlings but you can still plant instant colour seedlings and fast maturing varieties. In frosty regions it is time to sow winter and spring flowering seedlings such as pansy, cineraria, foxglove, aquilegia, Iceland poppy, viola, delphinium, larkspur and primula into seedling trays. Keep them moist and in a cool, shaded area. Store larkspur and delphinium seed in the refrigerator before sowing. In cold Highveld areas start preparing your trenches to plant sweet peas. Choose a sunny spot and dig the trench 250mm deep and wide. Mix generous quantities of mature kraal manure and compost into the soil before putting it back into the trench, and adding one cup of slow release fertiliser per running meter; water and allow the soil to rest until planting time.
In cold winter regions start sowing cool season vegetables such as Brussels sprouts, cabbage, cauliflower, kohlrabi and broccoli. Sow or plant Swiss chard, carrots, leeks, turnips, and parsnips; and do a final sowing of green beans.
Winter rainfall regions (Mediterranean)
January is one of the hottest months of the year and when the south-easter is blowing it dries out your soil quickly, so mulch your garden beds if you have not done so yet. Do not over fertilise this month; as this produces lots of soft, lush growth which wilts easily in the heat and wind, and requires more water. Water your shrubs and trees thoroughly and deeply once a week, as early in the morning as possible. You can also water late in the afternoon, as long as the leaves have time to dry out before nightfall. Windless, overcast evenings, combined with wet leaves, will encourage fungal diseases. You will need to water your seedlings and pots more often.
Replace tired bedding plants with heat-tolerant varieties like, portulaca, vinca, gomphrena and marigolds. You can still plant seedlings such as alyssum, begonia, balsam, cleome, candytuft, celosia, cineraria, chrysanthemum, cosmos, coleus, dahlia, delphinium, dianthus, gypsophilla, impatiens, larkspur, lobelia, nicotiana, nasturtium, petunia, pansy, poppy, phlox, rudbeckia, salvia, sunflower, verbena, viola and zinnia.
Start sowing cool season crops like broccoli, cauliflower, cabbage and Brussels sprouts into seedling trays this month and keep in a cool place. You can still plant or sow beetroot, brinjal, cabbage, cucumber, carrot, parsley, radish, spinach, sweetcorn, tomatoes, turnip, and heat tolerant lettuce. Make a final sowing of beans, baby marrow, gem squash, and patty pans.
Subtropical summer rainfall regions
January is one of the hottest months of the year, with lots of rain and high humidity; so don’t water in the evening, as this will promote fungal diseases; the best time to water is very early in the morning. Spray plants that are susceptible to fungal diseases regularly with an organic insecticide such as Ludwig Copper Count, or Biogrow Copper Soap. If you have yellow spots on your lawn, it could be a fungal disease, consult with your local nursery and spray with an organic fungicide if necessary. Rain quickly leaches nutrients out of the soil, so fertilise your entire garden regularly with a balanced organic fertiliser.
Keep a look out for insect infections like aphids and mealy bug; they thrive in hot humid conditions. Ants, white ants, scale and the rhinoceros beetle can also become problematic. Check your bromeliads for scale and spray them with Oleum if necessary; do this in the cool of the afternoon. Oleum is a mineral oil, which suffocates the scale, but can burn the leaves if sprayed in strong sunlight. Blast stagnant water out of the central vase of bromeliads with a jet of water; as this old stagnant water can breed mosquitoes. Mist spray your staghorn ferns with water daily.
Lightly prune your acalypha bushes to encourage new shoots and remove the flower spikes from your crotons. Nipping out the growing tips of poinsettias will encourage bushy growth.
Feed your avocado trees with an organic 3:1:6 to prevent the fruit dropping prematurely. Feed your bananas with 3:1:6 and keep them moist. You can also feed your paw-paws and mangoes with 3:1:6 or 2:3:2.
You can still sow seeds of alyssum, cleome, dianthus, salvia and nasturtium and you can still plant seedlings of cosmos, impatiens, marigold, vinca and verbena.
Sow peppers, tomatoes and eggplants now.
Dry, semi-arid and continental regions
Large parts of this region have very shallow soil, with rocky layers of shale underneath. These layers prevent the drainage of water around the roots of your plants. During very hot weather your plants may wilt, not from lack of water, but from too much water; so it is imperative that you water correctly. Water your shrubs and trees thoroughly and deeply once a week, as early in the morning as possible. You can also water late in the afternoon, as long as the leaves have time to dry out before nightfall. Windless, overcast evenings, combined with wet leaves, will encourage fungal diseases. You will, of course, have to water your seedlings and pots more often. Do not wet the leaves of your plants with brak (salty) water when the weather is very hot and windy, or the salts will burn the leaves. By installing rainwater tanks you will be able to grow plants that would not otherwise survive these conditions. Your pot plants will also thrive on rainwater. In very hot, dry areas with brak (salty) water, wait until autumn to sow and plant seedlings. Hot wind and the heat make germination difficult now. Rather, dig lots of compost into your flowerbeds and wait until autumn.
Mulch your garden beds and do not over fertilise this month, as this produces lots of soft, lush growth, which wilts easily in the heat and wind, and requires more water.
Sow winter and spring flowering plants such as pansy, cinerarias, foxgloves, aquilegia, Iceland poppies, viola, delphinium, larkspurs and primula seed in trays now. Keep them moist and in a cool, shaded area. Store larkspur and delphinium seed in the refrigerator before sowing. In cooler areas, you can still plant out alyssum, marigold, portulaca and zinnia.
Sow vegetables such as Brussels sprouts, cabbage, cauliflower, broccoli, Swiss chard, carrots, leeks, turnips, kohlrabi and parsnips.