Organic Spray

Chemicals & Roses

Chemicals & Roses

It started as a desire to stop using harmful rose sprays and having lots of them I wanted to mix my own from natural and organic sources to minimise harm to wildlife and bees. Now we have an International test going on.
The simplest thing to do is to grow disease resistant breeds. However, the most fragrant and beautiful roses I know of are prone to disease and need looking after. I do not mind the effort as the reward of beautiful roses and wonderful scent makes my heart sing.

The problem is that most of the treatments are harmful to wildlife and the environment and I am keen to use garden products that do no harm.
Probably the best known organic rose tonic is Uncle Toms. It is a very good product. Please read about it.

The Science Behind Uncle Tom’s® Rose Tonic

Amateur gardeners now have the opportunity to benefit from potassium phosphite, a nature-identical plant food. Widely used by professional growers the results have prompted recommendations from many of the leading members of the rose breeding and growing industry.

I am a passionate amateur rose gardener, it is not my day job, it is my safe place of sanity in a mad world. ‘How hard can it be to make my own?’ I thought one day, sounding like Jeremy Clarkson now.
There is a wealth of information out there. One article got me thinking:

Safe Rose Spray Recipe That Really Works – Horticulture

Looking for a safe rose spray to keep your plants healthy? Here’s the non-toxic recipe given to us by the gardeners at Hershey Gardens in Pennsylvania.

Looking at the Ingredients

Roses like acidic soil, ideally a pH of 6-6.5. With a cheap pH meter you can test your soils pH and add Cider or White vinegar in a feed to adjust the soil pH and the roses will thrive. You should always combine the vinegar with feed to ensure the plant is nourished. Too much vinegar will also kill plants. Baking Soda is known to help treat fungal disease on plants and so the combination of Vinegar and baking soda is logical.

The addition of the oil is to coat the foliage so that moisture runs off. There is dry weather and high humidity it is creates the perfect conditions for powdery mildew. This basic combination of ingredients works quite well on roses.

Taking it a step further

I got the idea from David Austin Roses @DAustinRoses in a tweet about organic rose treatments that garlic exudes natural Sulphur which rose treatments need to be effective. So I am testing my concoction with Garlic concentrate from an Equine supplier as it is used in horses as a tonic. Garlic acts as an anti-septic, anti-flammatory, and fly repellent. Most importantly it is rich in natural sulphur which kills fugal spores.

Equimins Garlic Extract Liquid – Equimins

Concentrated Garlic Extract. Many times stronger than powder or granules. Daily use will support the respiratory system in a way no other single herb does.

I decided to replace the vegetable oil with Neem oil because it kills pests and fights powdery mildew and blackspot. I use good quality oil used as a carrier oil in organic cosmetics and essential oil blends

Virgin Neem Carrier Oil | Naissance

Naissance 100% pure, unrefined, cold Pressed Neem Oil. A rich oil, viscous oil, packed with fatty acids and Vitamin E. Cruelty Free and Vegan Friendly

For soap I use again a natural organic soap so that I know I am not adding chemicals from dish soap

Certified Organic Liquid Castile Soap | Naissance

Naissance 100% natural, Organic Liquid Castile Soap. A natural, deep cleansing soap made from premium vegetable oils. Cruelty Free and Vegan Friendly

Sulphur Rose

In 2023 I started adding Sulphur Rose to the mixture. Black spot (Diplocorpon Rosae) is a fungus that manifests itself on Rose Bushes as black spots fringed with yellow rings on both sides of the leaves.

As the disease spreads, the entire leaf goes from green to yellow and drops to the ground if unchecked the black spot can affect the entire rose garden leaving the appearance of many bare-naked plants.
Grerenacres Sulphur Rose

I use the above products because I know they are top quality, I am not paid to promote these products. My interest in this is purely as a hobby and to share my experience with others via Twitter. They also sell smaller quantities if you only have a few roses. The key is to use good quality products.

The Recipe

Mixing 1 Gallon or 4.5 Litres

  • 2 Tablespoons of Vinegar (15 ml)
  • 2 Tablespoons of organic liquid soap (30 ml)
  • 2 Tablespoons of Neem Oil (30 ml)
  • 3 tablespoons of Garlic Concentrate (45 ml)
  • 3 Tablespoons Baking Soda (45 grams)
  • 2 Spoons of Sulphur Rose powder 5ml

Making a bottle of 750 ml in a spray bottle:

  • 2.4 ml of Vinegar
  • 5 ml of organic liquid soap
  • 5 ml of Neem Oil
  • 5 ml of Garlic Concentrate
  • 7.5 grams Baking Soda
  • 1/2 scoop of Sulphur Rose


I mix in a gallon sprayer and make sure I give it all a good shake before using. Ideally, it needs to be stored at room temperature and if the oil gets lumpy just put it in the airing cupboard or stand in a bucket of hot water for a while making sure it is cool before spraying.

Mixing Large Batches

Put all the ingredients except the baking soda into a 1 litre measuring jug. Add 400 ml of boiling water.
Carefully put the baking soda into the mixture do not stir or agitate, wait between spoons of baking soda for 30 seconds or so and gently stir.

Have a large bottle with a funnel ready, I use 1.5-litre water bottles. If the Bicarb fizzes up too much, quickly pour it into he the larger bottle. If this happens let it cool before putting it back in the measuring jug to accurately top up with water.

Leave for 15-20 minutes then top up to 1 Litre with hot water do not worry about the foam. Leave to cool then pour into spray unit or storage container and add 3.5 litres of water. I store this in 1 litre bottle of concentrate and add to spray unit before use.

If it is cold put the concentrate bottle into a bowl or bucket of hot water so that the oil melts and shake well.

Using Concentrate From I Litre bottle

If you use a small spray bottle 280 ml of the concentrate to 750 ml of water following the batch process above.

A note on spraying

The best time of day to spray is as the sun goes down. Do not water before. The leaves will be dry and the spray will be most effective. Do not spray just the surface of the leaves but underneath.

If you have any disease remove the diseased leaves and dispose of, do not compost and pick up any leaves around the base of the rose.

In these instances spray the stems and around the base, wash your hands and sterilise any secateurs or cutting tools to stop the spread of disease. We all have plenty of ant-bac wipes these days!

An Experiment

A group of Twitters gardeners are participating in an experiment to see how this goes on just one rose bush this season following this recipe. I have sent out my mixture so that we get consistent results and I will be posting more news on this.

Please do contact me via Twitter @JRRushden to discuss this and ask any questions.

Posted by Jason Richards in Plant Care, Roses, 0 comments