There are many home-made products that can be used around the garden in place of the harmful and expensive chemical herbicides and pesticides that that line garden centre shelves and many of them do at least as good a job as the proprietary brands.  It has to be said that there are many more useless remedies out there than useful ones, and a few more that are actually harmful, so beware the weird and the wacky, and be sceptical of too-good-to-be-true claims. No single preparation can do it all, despite numerous declarations  to the contrary, but some can work unexpected  wonders on specific problems.

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Water

It can’t get much cheaper than water! Cold water sprayed on plants which are susceptible to powdery mildew can be as effective as any of the powdery mildew sprays that are available on garden centre shelves, and boiling water poured on troublesome weeds or annoying insect nests is about as simple and cheap as you can get.  The difference is in the number of applications as you will have to repeat the treatments on target plants to remain on top of the situation.

 

Traps

Use traps to monitor the health of your plants before there is a problem. A few sticky yellow cards hanging around plants, inside or outside, beer or milk traps in the garden to monitor (and kill) the slug population and a nice big magnifying glass are all indispensible tools in the garden.

 

The best way to control slugs in the garden is to put out well designed slug traps baited with milk or beer and ensure that they are topped up (with bait) and emptied (of bodies) on a regular basis. Slug pellets are expensive, poisonous and unnecessary and milk and cheap, yeasty beer are readily available and very effective.  A little extra protection in the way of ash rings around tender seedlings will finish the job.

 

Bucket traps

Some large pests such as lily beetles can be easily dislodged by filling a bucket with an inch or two of water and holding it under the affected plant while giving the plant a vigorous shake. It couldn’t be simpler.

 

Yellow stickies

Insects are often attracted to the colour yellow and you can use this to your advantage by making your own yellow sticky cards to monitor and trap small insects such as white fly and aphids in conservatories and greenhouses. These cards can be made in minutes by cutting out rectangles of yellow card or plastic and coating it with a sticky mixture made of equal parts petroleum jelly and washing up liquid. Pierce a hole in the middle top of the card and thread a paper clip through it and use that to hang the cards on the plants. Beware though that these traps will trap beneficial insects as well.

 

Tape traps

Persistant aphids, whitefly and mites can be quickly lifted from the undersides of large leaves by good old sticky tape. Wrap a couple of lengths of sticky tape around your fingers, sticky side out, and gently roll the tape along the underside of the leaf and  discard the tape and the offending beasts in the bin.

 

Tea and vinegar

 If you grow blueberries, camellias,  rhubarb or any other acid loving plant and you garden on neutral to alkaline soil, you will be engaged in  a permanent battle to  lower the pH, and here is where homemade apple cider vinegar comes in. If your soil is only mildly alkaline try watering around your acid-loving crops once a week with one cup of vinegar mixed in to a one gallon of water to lower  the pH of the soil. Do not apply directly to the leaves. Tea bags, reclaimed from the kitchen and left to soak in your water butt, will do the same job.

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Dont apply vinegar undiluted as on its own it acts as a contact weed killer of annual weeds. It won’t penetrate the ground sufficiently to kill off the roots of perennial weeds, but it can clear ground temporarily. You can exploit this if you are looking to top kill a small area in order, for instance, to lay down a layer of mulch. First try a mix of 1:1 water:vinegar mix, and if that doesn’t do the job increase the strength by cutting out the water completely.

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There are always apples that are free for the taking in apple season, whether they are from wildings, from community orchards or through social media sites like Freecycle, and making up a batch of apple cider vinegar is an easy way of acidifying soil or making your own spot weed killer.

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To make a beginners batch of  vinegar: fill a gallon jar half full of chopped apples (any variety, cores, skin and blemishes intact) and add a heaped cup of sugar then fill the jar with water, cover with cheesecloth to  keep out fruit flies,  and leave it on the counter for a month or so. As soon as it tastes like vinegar, strain it and store it in sealed bottles and jars. If you have a good supply of apples you will be able to make a very respectable quantity of vinegar, enough to last through the year!

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Garlic and pepper sprays

There is no doubt that garlic has anti-fungal and anti-microbial  properties  - it is often recommended to combat powdery mildew –but its main use in the garden is undoubtedly  as an insect repellent that can be used against sawfly and beetle larva on shrubs and trees, whitefly in the greenhouse and an excellent slug repellent on hostas. To make up a smelly but hightly effective garlic wash simmer  6 cloves of garlic in 1 pint of water and leave them to soak for an hour, then strain and make it up to one gallon with cold water.  Stir in a tablespoon of pure liquid soap to make it stick to the leaves, then spray it onto your plants until the wash drips off. If necessary continue spraying on a weekly or fortnightly basis.

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Hot peppers also work as an insect repellent though not because of the way they smell but of how they taste, and they are especially valuable as you can use them inside where a garlic spray would be intolerable. Blend 1 cup of fiery hot peppers with 2 to 3 cups of water, then strain and add a teaspoon of liquid soap to use as a wetting agent.  Use the spray  as an insect repellent on greenhouse crops and houseplants. Pepper spray won’t  kill insects, but it will stop them from eating a specific plant.

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Horticultural Soaps

Horticultural soaps are contact insecticides and they must come into direct contact with the pest at the time of spraying. There are several  theories about how these  soaps work; that they disrupt cell membranes, that they clog the spiracles -  the breathing holes through which insects breathe -  or that they remove their waxy coating which causes the insects to dry out, but what is not in dispute is that they do work, and very effectively at that. There are two types of insecticidal soaps; simple horticultural soaps that work purely by physical actions and insecticidal soaps that have an added chemical pesticide.  

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You can make up a batch of horticultural soap by adding a tablespoon of natural soap (liquid or fine shavings from a bar of pure soap) to a litre of water and stirring it until the soap has dissolved. Pour the liquid into a spray bottle and spray it onto the infected plants, targeting the area that is infested. The more precise you can be with your spraying the better the results.

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Only use pure soap such as castile soap, pure laundry or household soap such as Soap Flakes or any other vegetable or animal based soaps that contain no detergents, fragrances, moisturizers or enzymes.  Most washing up liquids are detergents, not soaps so should not be used.

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For very persistent infestations or hard to  control insects such as mealy bugs and scale, up the ante by adding a minced garlic clove or a couple of minced chilli peppers to the soap mix, strain it through a fine sieve and use as before, or dip an ear bud in the mix and wipe the bugs off with it.

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Pyrethrum

The most effective home-made insecticidal remedy is made of the flower heads of an easily grown garden plant, but do remember that it is as effective a killer of beneficial insects as of pests, so always use carefully and only when there is no alternative.    Pyrethrum daisies (now listed as Tanacetum cinerariifolium  and T. coccineum) belong to the chrysanthemum family and are closely related to the common or garden herb, feverfew, and to the cottage garden flower that still goes by the name Pyrethrum. You can grow T.  cinerariifolium in your garden and make up an infusion of a highly effective insecticide to target persistent or very damaging pests such as cucumber beetles or squash bugs.  

Pyrethrum is toxic, no doubt about it – it’s lethal to invertebrates and to fish; and while it doesn’t affect birds and mammals in the same way, one must take care nevertheless. The only way to exploit   the toxicity of pyrethrums while safeguarding beneficial insects  is to direct target the pest species late on a calm, still evening,  then immediately cover the plants with horticultural fleece and leave it in place for 24 hours to exclude bees, butterflies and other non-target insects. Pyrethroids are most effective in the cooler temperatures of night-time and will remain active for about 12 hours after being exposed to sunlight.

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To make pyrethrum spray cut the flower stalks and hang them upside down for 24 hours before trimming off the  flower heads with a small piece of stalk and laying them out in an shaded airy place until they are dry. The freshly dried flowers will keep for about 10 days if stored in an air-tight container in the fridge, and for about 6 months in a sealed bag in the freezer. When required, crush the flowers finely and mix 5 grams of the crushed flowers into 1.5 litres of water and soak for 3 hours,  then strain and put into a spray bottle. The addition of ½ teaspoon of liquid soap (not detergent) to the infusion will improve the efficiency of the spray by allowing it to stick to the insects. To dispose of any unused spray poor it onto a concrete or non porous surface outside in the sunlight where it will be rendered inactive. Do not pour it away in drains or on the garden.

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Mulch

Mulching around roses with grass clippings and practicing excellent hygiene by removing infected leaves and damaged stems and tidying away all leaves and twigs as they fall is a good natural remedy to control black spot in roses as it interrupts the life-cycle of the causal organism and doesn’t add to  the cause by

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Baking Soda

The last word in home remedies must be given to baking soda, which is undoubtedly the darling of many a gardener. There is no doubt that it is cheap and safe to use  if it is properly diluted at the correct dose (it can burn foliage if the solution is too strong) and there is no question that it is effective against powdery mildew, but then again, so is water. However, there are quite credible claims made by farmers and professional growers that it is also effective against blackspot on roses and blight on potatoes and tomatoes as well as on grey mold...but there are also equally credible claims that is not. One thing that everyone agrees on is that baking soda should not be used too often, for  fear of burning the foliage, but when it is used it should always be combined with a wetting agent and an emulsifier.  There are as many recipes for this mix as there are advocates, but this one is representative. Give it a go and let me know...I am dying to find out if it works! To make up a batch mix  3 tablespoons baking soda, 1 tablespoon vegetable oil and 1 teaspoon pure soap mixed into 1 gallon of water, then spray  to run off. Repeat weekly.

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• When applying any insecticide, investigate the spray area closely to see if there are any creatures that could be affected by your activities. Spraying to remove a pest won’t do much good in the long run if you wipe out a population of predatory insects at the same time!

• Always exercise caution: remember that homemade does not necessarily mean harmless. Chemicals are chemicals, whether they are derived from the plant that grows around your garden gate, or from synthetics in a laboratory. Homemade, does, though, generally mean that you know exactly what you are using down to the exact ingredient, and it almost always means cheaper! 

• Never spray pyrethroids near ponds or streams and never spray on a breezy day where the  spray could be blown onto nearby plants or surfaces.

• Always test your preparations on a small area of the plant first then leave it for a couple of days and only proceed if there is no sign of leaf burn.

• Always wear gloves to protect your hands and a head covering if you are spraying anything above head height.