My Science School

•  Poison rose black spot with tomatoes

It's long been known that roses grown next to tomatoes are less likely to fall victim to black spot. Make a fungicide by snipping tomato leaves from a plant and processing them in a blender with a little water; use enough leaves to make 2 cups (500ml) slurry. Combine with 1.5 litres water and 2 tablespoons cornflour and mix well. Store the solution in the fridge, marking it clearly with a warning label. Spray your rosebushes once a week with the fungicide.

•  Repel caterpillars with onion juice

Spray cabbage and other vegetables that are targeted by caterpillars with onion juice and watch them take a detour. To make a spray, peel 2 medium-sized onions, grate them into a large bowl and add 4 litres water. Let the mixture sit overnight, then strain it into a spray bottle. To make the plants smelly enough to repel the pests, you may need to spray the leaves twice.

• Soup-can stockades

To keep cutworms and other crawling pests from reaching newly planted seedlings, use soup cans as barriers. Cut the top and bottom out of a can, wash it well, then place it over a seedling. Twist it until the bottom is 5cm underground and your tender seedlings will gain protection from all directions. Paper cups with the base cut off can be used in the same way.

• Fight fungus with bicarbonate of soda

Keep powdery mildew, black spot and other fungal diseases from infecting your fruit trees, vegetables, gardenias, roses, etc., with a bicarbonate of soda solution. In a large spray bottle, combine 1 teaspoon bicarbonate of soda, 1 teaspoon washing-up liquid and 1 litre warm water. Shake well and spray plant leaves and stems on both sides to discourage fungal diseases from taking hold.

•  Bleach out pots

When repotting patio plants, sterilize flowerpots and planters to keep your precious newly purchased plants from succumbing to fusarium wilt or leaf curl. First plug the drainage holes with clay or putty. Then scrub off any caked debris with a scrubbing brush or toothbrush. Rinse the pots and fill with a solution of 1 part household bleach to 4 parts water. Let it stand for 2-3 hours. Discard the bleach in the laundry sink (not the garden), rinse the pots with fresh water and let them air-dry.

• A bubble wrap warmer for camellias

Camellias grown in containers are particularly sensitive to the cold because of their shallow roots. When winter comes, wrap the camellia pot with thick plastic bubble wrap or several sheets of newspaper and secure the wrap with gaffer tape. Turn the pot so that the tape is out of the sight line of visitors.

•  Polystyrene pellets as a drainage aid

Instead of putting rocks or pot shards in the bottom of a patio planter, fill the bottom quarter with the polystyrene pellets used for packing. What do they have over rocks? They make the planters lighter and allow you to use less potting soil.

•  Plastic raincoats for exposed furniture

When heavy rain is forecast and you don't have enough indoor space to bring your patio or garden tables and chairs inside, cover them with plastic dry-cleaning bags.

•  Bubble away rust with vinegar and bicarb

If you have a concrete patio and metal furniture is leaving rust stains, try pouring full-strength white vinegar on the stains, top the puddle with a little bicarbonate of soda and leave it for about 10 minutes before wiping it off with an absorbent cloth. Older rust stains may need two or three more applications before they disappear.

•  Wicker basket to hanging plant

Finally, here is a use for the wicker basket you have had stuck in the back of the cupboard for years. First use varnish to weatherproof the basket, then line the inside with a plastic garbage bag with a few drainage holes poked in it. Dig up four or five of the plants in your flowerbed, transfer them to the basket and you've made a hanging planter for the patio.

•  Discourage mosquitoes

To stop mosquitoes and other insect larvae from breeding in birdbaths or water features, put a few drops of vegetable oil on top of the water. The oil spreads to form a film over the surface, ensuring that mosquito larvae won't be able to breathe through the water's surface. Renew the oil every week throughout summer.

•  Herbal mosquito repellents

Steep a few pennyroyal or fleabane leaves in hot water and let them sit for 4-6 minutes. Strain the solution into a spray bottle and spray onto patio plants to repel mosquitoes. Or do the same with some garlic cloves. Simmer about 8-10 peeled garlic cloves in 2 cups (500ml) cooking oil for about an hour. Cool, strain into a spray bottle, then you're right to spray away.

•  Fool codling moths with fake apples

The larvae of these moths attack fruit such as apples and pears, but you can make sure that codling moths never lay eggs by luring them with fake apples — red Christmas tree balls hung in fruit trees. Start by threading a 30-cm loop of string through the ball holder, and then knot it two or three times. Spray the 'apples' on all sides with an adhesive insect spray and hang three or four on fruit-tree branches. The codling moths will home in on the red targets and get stuck.

•  Bottle up wasps

Wasps follow their noses to sugar, so set them a sweet trap. Slice 7cm off the top of a large plastic soft-drink bottle and set it aside. Create a hanger by poking holes on either side of the bottom of the bottle, near the top. Thread 45-60cm string through the holes and triple-knot the ends. Place the cut-off piece with the neck attached into the bottle upside down to form a funnel and tape it tightly.

Pour sugar water into the bottle (use 4 parts water to 1 part sugar, dissolved) and hang your contraption on the branch of a tree that is frequented by wasps. Wasps trying to reach the liquid will be unable to escape from the bottle and then drown.

•  Repellents in your herb rack

We love herbs and spices, but most garden pests find them unpalatable or even lethal. Sprinkle any of the following around your plants and watch leaf-hungry pests go elsewhere to dine.

1.  Ground cinnamon


2.  Ground cloves


3.  Cayenne pepper


4.   Black pepper


5.  Chilli powder


6.  Hot curry powder


7.  Garlic powder


8.  Dried lemon thyme


9.  Dried bay leaves, crumbled.

•  Repel aphids with aspirin

The active ingredient in aspirin, salicylic acid, is produced by plants as a natural protection — and that works to the gardener's advantage. Experiments have shown that plants watered with a weak aspirin-and-water solution not only repel aphids and other sucking insects, but also promote strong plant growth.

To make a systemic solution, fill a bucket with 20 litres water and drop in 3 aspirin tablets. Stir until the tablets dissolve. Water plants as usual with the solution or pour it into a spray bottle to spray the plants' leaves and stems on all sides. Thereafter, apply the aspirin water every two weeks.

•  Send insects to a mothball chamber

If whiteflies, mealy bugs or other insect pests are attacking houseplants, then consider instituting death-by-mothball. Put an affected plant (pot, saucer and all) into a clear plastic dry-cleaning bag. Water the plant and drop 5-6 mothballs into the plastic bag.

Next, tie the bag closed with a twist tie, then move the bagged plant to a bright, though not directly sunlit, spot. Let it sit for a week before taking the plant from the bag and returning it to its usual place. If necessary, repeat the treatment until all of the pests have given up the ghost.

•  Attract pests with warm colours

Paint milk cartons red, orange or yellow, coat with petroleum jelly or an adhesive insect spray, then put them at 4-m intervals in the garden. Flying insects will fly into them and get stuck. To kill aphids in particular, forgo the petroleum jelly and simply fill yellow container three-quarters full of water. The little green insects will zip straight to the container and end up in a watery grave.

•  Let toads do it

Toads are among the most insect-hungry garden visitors. Attract them by placing a broken flowerpot or two in a shady spot, and then sink a dish filled with water and rocks into the soil so that any visiting toads will stick around.

•  Get rid of squash vine borers with kerosene

You can prevent squash vine borers from attacking zucchini and pumpkins even before you seed these plants. Soak the seeds in kerosene overnight. The seedlings and mature plants will be able to repel borers — but the kerosene won't infiltrate or affect the fruits.

•  Eradicate earwig with vegetable oil

Earwigs are extremely partial to clematis, chrysanthemums, dahlias and gladiolus — so how do you give the hungry little creatures the brush-off? Not with a broom but with oil, an earwig favourite. Pour a pool of vegetable oil onto a saucer, leave it on the ground among your flowers and the earwigs will crawl into the saucer and drown.

• Protective fabric-softener sheets

Keep mosquitoes from dive-bombing you as you work in the garden by tucking a few fabric-softener sheets into your clothing, or wipe the sheet directly onto your skin. Another great idea is to dab a little vanilla extract onto your pulse points and around your neck — it might be attractive to humans, but it will drive away the mosquitoes! Or, if you're eating outdoors, put small bowls of water, with a squirt of lemon-scented detergent in them, nearby.

•  Help birds to build nests

To attract birds to your garden in spring (they will happily feast on leaf-eating insects when not eyeing up your vegetables or fruit in summer), hang some nest-building materials in a tree. Fill a large, mesh onion bag with lint from a tumble-drier, hair from a hairbrush, fabric scraps and short pieces of string or wool. Then watch your feathered visitors fashion a new home.

•  A real flap

If you're in a windy spot and are trying to discourage birds from landing on garden plants, cut plastic rubbish bags into 'flags' or long strips and staple them to tall wooden stakes using a staple gun. When the plastic whips around in the wind, birds will be scared away by both the movement and the noise. Hanging up old CDs also frightens them off.

•  Scarecrow stuffers

If you decide to put a traditional stand-up, hatted scarecrow in your vegetable plot (as much for nostalgia as anything else), be aware that the stuffing materials for his shirt and pants are probably already in your home somewhere.

Anything soft and pliable will do as long as you seal it into a plastic garbage bag to keep it dry: old pillows, rags, wadded-up newspaper, bubble wrap, polystyrene packing chips, shower curtains or dust cloths. And don't forget old-fashioned hay, straw and dead leaves.

•  Guard garden plants with garlic

Encircling a flowerbed or vegetable plot with garlic plants will discourage many furry pests —including bush rats and field mice — from making a meal of your plants. Space the garlic about 15cm apart to ward off hungry intruders.

•  Possum chasers

Possums are a major problem for gardeners in some areas, and are particularly destructive to roses. Make a tea with 1 litre hot water poured over either 2 tablespoons crushed garlic or crushed hot chilli. Allow to stand overnight, then filter and decant into a spray bottle. Spray onto foliage and repeat after any rain. Other repellents to try include:

1.  Fish fertilizer sprayed at recommended strength.


2.  Blood and bone sprinkled around bushes and trees.


3.  A paste made of Vaseline and a crumbled block of camphor (used as a moth repellent in household cupboards) applied to stems.

•  Rabbit rebuffers

Plenty of repellents will turn rabbits away from your plants. Among those to try are:

1.  Hair from humans, dogs or cats.


2.  Talcum powder, dried chilli flakes or garlic powder, dusted around plants.


3. Bars of strongly fragranced soap placed in vegetable garden rows.


4.  Lemon peel scattered among plants.

•  Flag down deer

Deer have become a nuisance in parts of New Zealand and Australia. However, white 'flags' made from white plastic shopping bags, rags or strips torn from old T-shirts could help to keep them out of vegetable gardens. The movement of something white mimics the deer's warning signal — flashing the white underside of its tail — that predators or other dangers are imminent.

Hammer 60-90cm-tall stakes around your plot at 2-m intervals. Tack plastic shopping bags to the stakes so that they billow in the wind or attach white fabric strips that are long enough to flutter in the breeze. If you're lucky, deer will run the other way when the white flags fly.

•  Coat-hanger cold frame

To protect seedlings in heavy planters that you are unable to bring indoors when it's cold, straighten out two wire coat hangers and then bend them into arcs. Cross them and insert the ends into a planter just inside the rim, leaving headroom for the seedlings. Cover this wire frame with a plastic dry-cleaning bag, securing the plastic to the planter by wrapping it with loosely tied string. Temporarily remove the plastic whenever the seedlings need watering.

•  Extra insulation

If you are keeping seedlings or hardening off young plants in a cold frame and a hard frost is forecast, line the inside of the frame with sheets of newspaper; it's a first-rate insulator, as is bubble wrap, if you have any handy.

•  A newspaper blanket

When a frosty night has been forecast, make tents from thinnish sections of newspaper and place them over seedlings, weighting them down at the edges with stones. They will keep your plants nicely insulated from the cold until the temperature climbs the next day.

•  Baskets of warmth

In cool climates, old-fashioned woven baskets make excellent plant protectors, keeping cold winds out while letting in some light - look around for old broken baskets you can leave outside in the wet. At night, drape them with black plastic for extra protection.

•  Improvised cloches

 The French came up with the idea for the glass cloche, or bell jar, to protect seedlings from frost. Elegant glass and practical plastic cloches line the shelves at garden centres, but a simple household substitute will do the job just as well. Some ideas for plant protectors include:

1.  A tall flower vase, placed upside down over the plant.


2.  A large-glass fruit jar.


3.  A 2-litre soft-drink bottle. Slice the bottom off with a sharp knife and place the bottle over the seedling.


4.  A 4-litre juice bottle, used in the same way as the soft-drink bottle.

•  A warm cosy glow

If frost threatens to damage a large container plant sitting on your patio or verandah, or perhaps a tree that's bearing young fruit, string Christmas lights through the branches. Cover the plant with an old sheet and switch on the lights. Your plant will stay warm and frost-free throughout the night.

•  Pinpoint weeds with salt

Salt will kill many weeds that can't be pulled up from the roots. Use a garden fork to scrape the soil away from the base of the weed and then cut the stem as close to the ground as possible. Pour salt onto the wound, trying your best not to spill any into the soil.

•  Drive weeds from cracks using salt and vinegar

If weeds or grass sprout from cracks in your driveway, path, patio or any other outdoor paved surface, squirt them with a salt and vinegar solution. To make it, combine 2 cups (500ml) vinegar, 2½ tablespoons salt and 2 drops washing-up liquid in a jar, screw the cap on tightly and shake well. A simpler alternative is to pour boiling salted water into the cracks. When applying either weed killer, make sure that no run-off reaches your plants.

•  Newspaper and plastic smotherers

If one part of your garden seems a little too weed-friendly, try one of these mulches to keep undesirable plants from sprouting:

1. Newspapers Wet several sheets of newspaper so that they cling together and then lay the mat over a patch of weeds. Camouflage the mat by topping it with wood chips or other mulch. Remove it once the weeds have died.


2. Garbage bags Split the seams of black plastic bags to double their size and use them to blanket the problem spot. Cover the plastic up with wood chips or a similar camouflage and leave it in place for 10 to 14 days — by which time the weeds should be dead.

•  Free mulch quest

Mulch is usually there for the taking if you know where to look for it. Besides the dead leaves and grass clippings you can collect from your own garden, check with agricultural businesses and local governments to see if they have any waste material that they would like to be taken away. In particular, ask for items such as chipped bark and wheat straw.

•  Strawberries love sawdust

Sawdust mulch benefits strawberries in two ways: it gives them the acidity they crave and keeps snails and slugs at bay. Raise the foliage of each plant and mound sawdust 5-7cm high around the stem. But be aware of what you're using: sawdust from certain species, such as cedar or chemically treated wood, may contain toxins that are not suitable for garden plants.

•  Recycle the tops of root crops

What can you do with the leafy tops of the carrots, beetroots, radishes and other root vegetables that you grow? Once you have harvested the roots, lay the tops between rows of your vegetable garden to mulch the crops that remain.

•  Black plastic for a small space

If you have a tiny garden — say a 1.5 sq m patch of soil in a paved courtyard — don't bother to buy the black plastic mulch sold at garden centres. (Black plastic is the standard weed-eliminating underlay for bark-chip mulches.) Plain, black plastic garbage bags will do the job equally well. Just spread out the bags side to side — and when it comes time to restyle your small garden months or years later, you can use the bags for their original purpose — to hold rubbish — so you'll be saving money and recycling, too.

•  Foil and paper heat-beaters

Single-layer mulch made from aluminium foil or brown paper (the latter coated with clear varnish) will help to decrease soil temperature because both materials reflect the sun's rays. On very hot days, keep the roots of a favourite plant cool by laying foil or paper around the base of the plant, taking care to keep it away from the base of the stem.

• A matchbook fertilizer

This is for when you want to add sulphur to the soil to lower the pH for acid-loving plants. Tear out the matches from several matchbooks and throw them into the bottom of planting holes for such plants as hydrangeas, azaleas and gardenias. Add onion skins for extra effect.

•  A freebie from the fireplace

Hardwood ashes from a fireplace will supply potassium and phosphorous to the garden. But don't use wood that has been treated with preservatives (or anything else). To fertilize plants, spread a 1-cm layer of ashes a few centimetres from the stem and dig into the soil. Caution: If you store ashes outside, protect them from the rain or their nutrients will be depleted; and don't use ashes around potatoes, as ash can promote potato scab.

•  Limit your plants' coffee consumption

It isn't the caffeine in coffee grounds that garden plants like azaleas, rosebushes and evergreens love, but rather the acidity and aeration that the grounds provide — not to mention nitrogen, phosphorous and trace minerals. Just be sure to dig the grounds well into the soil to keep them from becoming mouldy.

Dig about 100g coffee grounds into the soil near the roots, repeating once a month. And don't overdo it: fertilizing even acid-loving plants with coffee grounds too frequently could increase soil acidity to undesirable levels.

•  A tree-feeding drill

To make sure that fertilizer reaches a tree's feeder roots, put a power drill to work on something besides wood: the soil. Use a bit at least 30cm long and 20mm in diameter and bore holes in the soil around the drip line — the imaginary circle beneath the outermost tips of the tree canopy. Space the holes about 60cm apart, then bore a second ring of holes about 75cm from the tree trunk. Funnel a slow-release fertilizer into all of the holes. Plug them with soil and water well.

•  Add sawdust and leaves to ageing manure

Fresh or raw, manure must be aged so that it doesn't burn your plants' roots — and only the most committed home gardeners will be prepared to wait the six months it takes. If you're one of those gardeners, water a fresh manure pile, cover it with a tarpaulin so that the nutrients won't leach out during rain, and turn the pile with a pitchfork every 10 days or so. To control the odour (especially in summer) and create an excellent texture, add untreated sawdust, dead leaves or wood chips.

•  Use a toothpick to test when it's time to water

Just as you can test a baking cake for readiness by sticking in a wooden toothpick, you can do the same to see whether a flowerbed is in need of watering. Stick the toothpick into the soil as far as it will go, then examine it. If it comes out clean, it's time to water. If any soil clings to the pick, you don't need to water just yet — test the soil again the next day.

• Saving splashes...

Flat smooth stones collected on a trip to the beach can be used as a splashguard in a window box. Watering plants in window boxes often splashes mud onto windowpanes, as does driving rain. To solve the problem, simply spread some water-smoothed pebbles over the surface of the soil. They look great and also help to retain moisture.

•  Recycle unsalted cooking water

Boiled foods release nutrients, so why pour their cooking water down the drain? Let the water cool and then use it to give a garden plant a healthy drink. Caution: when cooking any of the following, do not add salt to the water as it is harmful to many plants. Try these foods:

1. Eggs Boiled eggs leave several minerals in the cooking water, so use the cooled liquid to water calcium-loving solanaceous plants such as tomatoes, potatoes and all peppers.


2. Spinach Plants need iron too — and spinach water gives them not only iron but also a good dose of potassium.

•  Milk-bottle trickle irrigation

Tomatoes aren't the only garden plants that like lots of water. Other thirsty plants include zucchini and rosebushes. How can you keep their thirst quenched? Bury plastic milk-bottle reservoirs alongside each plant. Start by perforating a bottle in several places. Dig a planting hole large enough to accommodate both plant and bottle and bury the bottle so that its opening is at soil level. After refilling the hole and tamping down the soil, fill the bottle with water. Then top it to overflowing at least once a week and your plant's roots will stay moist.

•  Water ferns with weak tea

When planting a fern, put a used tea bag into the bottom of the planting hole to act as a reservoir while the fern adapts to its new spot; the roots will draw up a bit more nitrogen. Another drink ferns like is a very weak solution of household ammonia and water (1 tablespoon ammonia to 1 litre water), which will also feed them a little nitrogen.

•  Cocktail time for plants

After serving summer drinks, save any stale club soda to give to your plants. It adds minerals to houseplants when watered into the soil.

•  While you vacation...

Houseplants will survive well while you take a short holiday if they are placed in the bathtub or in the kitchen sink (if it's big enough to fit). Add water to the tub or sink, but no more than one-third of the pot's height. Too much water will cause sodden soil. Plants need oxygen for their roots and will die if pots remain saturated. If you have a collection of pots to keep moist while you're gone, the one-third rule applies to the shortest pot.

•  Hose punctured?

If water is leaking from a tiny hole in your garden hose, stick a wooden toothpick into the hole and then break it off at surface level. Wrap electrical tape or gaffer tape around the hose to secure the toothpick. The wet wood should swell up and form a tight seal.