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These are five knapsack sprayers, from 10 to 20 litres. The Solo 473D suits most grounds and gardens, with a diaphragm pump and a pressure gauge. Choose the Solo 10L 90psi for a 4 bar diaphragm pump in a UV-resistant tank, or the Solo 425 if you have more ground to cover between refills.
Sprayers Compared
Every column below is what the Amazon listing itself states. Where a listing gives two figures, both are shown; where it gives none, the cell says so rather than guessing.
| Product | Capacity, as listed | Pump and pressure, as listed | Award |
|---|---|---|---|
| Solo 473D Classic | 10 litre (title) / 12 litre (text) | diaphragm, 4 bar | Best Overall |
| Solo 10L 90psi | 10 litre | diaphragm, 4 bar / 90 psi | Best Professional-Grade |
| Solo 425 | 4 gallon (no litre figure listed) | piston, up to 90 psi | Best 15L Backpack |
| Matabi Super Green 12 | 12 litre (title) / 16 L (table) | not stated; 3-position regulator | Best Budget |
| Oregon 20L | 20 litre | not stated | Best 20L Backpack |
Best Overall — #1 Solo 473D Classic Backpack Sprayer
Product
Solo 473D Classic Backpack Sprayer — 10 Litre, Diaphragm Pump
Best Overall
- Capacity stated two ways on the listing: 10 litre in the title, 12 litre in the feature text
- Diaphragm (membrane) pump, as listed
- Maximum spraying pressure listed as 4 bar, with a pressure gauge
- 50 cm spray tube, as listed
- Empty weight listed as 3.9 kg
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Our overall pick if you want one knapsack for grounds and gardens. It has a diaphragm pump listed at 4 bar, a pressure gauge so you can see what the tank is doing and a 50 cm spray tube, and it weighs 3.9 kg empty. The listing gives 10 litre in its title and 12 litre in its feature text, so plan around the smaller figure.
Pros:
- Diaphragm pump, as listed
- Pressure gauge, maximum listed at 4 bar
- 3.9 kg empty
- 50 cm spray tube
Best Professional-Grade — #2 Solo 10L 90psi Diaphragm Pump Backpack Sprayer
Product
Solo 10L 90psi Diaphragm Pump Backpack Sprayer
Best Professional-Grade
- 10 litre, as listed
- Diaphragm pump, as listed
- Maximum working pressure listed as 4 bar / 90 psi
- 50 cm lance, as listed
- Listed at 4.2 kilograms; container listed as UV-resistant plastic
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Pick this one if you want a 10 litre diaphragm sprayer with its pressure given in both units: 4 bar, or 90 psi, maximum working pressure. It has a 50 cm lance and a container listed as UV-resistant plastic. The whole unit weighs 4.2 kilograms.
Pros:
- 10 litre with a diaphragm pump
- Maximum working pressure 4 bar / 90 psi, as listed
- UV-resistant plastic container
- 50 cm lance
Best 15L Backpack — #3 Solo 425 4-Gallon Professional Piston Backpack Sprayer
Product
Solo 425 4-Gallon Professional Piston Backpack Sprayer
Best 15L Backpack
- Capacity listed as 4 gallons; the listing gives no figure in litres
- Piston pump with a pressure range up to 90 psi, as listed
- Four nozzles listed: adjustable, fan, hollow cone and jet stream
- 20-inch wand and 48-inch hose, as listed; Viton seals
- Listed at 4.49 kg; made in the USA, as listed
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The larger Solo, for when you have more ground to cover between refills. It holds 4 gallons, has a piston pump rated up to 90 psi and comes with four nozzles: adjustable, fan, hollow cone and jet stream. A 20-inch wand on a 48-inch hose gives you reach, the seals are Viton, and the listing gives no litre figure.
Pros:
- 4-gallon tank
- Piston pump up to 90 psi
- Four nozzles: adjustable, fan, hollow cone, jet stream
- Viton seals; 20-inch wand, 48-inch hose
Best Budget — #4 Matabi Super Green 12 Garden Sprayer
Product
Matabi Super Green 12 Garden Sprayer 12L
Best Budget
- Capacity stated two ways on the listing: 12 litre in the title and text, 16 L in the detail table
- 3-position pressure regulator, as listed
- Fibreglass lance and four nozzles, as listed
- Padded, adjustable straps and a lateral liquid indicator, as listed
- Listed at 3.2 kilograms; pump type not stated
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Suits a garden of up to 400 square metres, the size the listing gives. It weighs 3.2 kilograms and has a fibreglass lance, four nozzles, a three-position pressure regulator, padded adjustable straps and a lateral liquid indicator so you can see the level from the side. The listing gives 12L in one place and 16 L in another, and does not state the pump type.
Pros:
- 3.2 kilograms, as listed
- Three-position pressure regulator
- Fibreglass lance and four nozzles
- Padded, adjustable straps
Best 20L Backpack — #5 Oregon Backpack Sprayer, 20 Litre
Product
Oregon Backpack Sprayer, 20 Litre
Best 20L Backpack
- 20 litre tank, as listed
- Lance and hose of about 2 metres, four nozzles, as listed
- Spare seal kit listed as included
- Listed for pesticide, lawn feed, weed and moss killer
- Listed at 3.93 kilograms; pump type and pressure not stated
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The biggest tank on this page, for large grounds where refilling eats into your time. It holds 20 litres, with about two metres of lance and hose, four nozzles and a spare seal kit, and the listing names pesticide, lawn feed, weed and moss killer as uses. It states no pump type and no pressure, so check those before you buy.
Pros:
- 20 litre tank
- Spare seal kit included
- About 2 metres of lance and hose, four nozzles
- Listed at 3.93 kilograms
Start with your situation
- You will be spraying for someone else, or were born after 1964. HSE’s certificate rule for pesticides — who may spray.
- You have a product marked for professional use. HSE says the general public must not use it, in any sprayer — who may spray.
- You are treating one room or one nest. A 10 to 20 litre tank on your back is the wrong tool — is a knapsack right.
- You want a diaphragm pump and a pressure figure the listing states. Two here — the Solo 473D and the Solo 90psi.
- You want the largest tank. The Oregon is listed at 20 litres, with no pump type or pressure stated.
Warning
A sprayer bought freely does not change what its contents allow. The label on the product you put in the tank decides who may apply it, where, and with what protection — the sprayer’s listing says nothing about that and neither does this page.
Is a Knapsack the Right Tool?
These are 10 to 20 litre tanks worn on the back, and every listing here sells them for gardens, allotments, orchards and grounds. The Matabi listing scopes its own tank to gardens of up to 400 square metres. A single room, a wasp nest or a skirting run is a hand sprayer’s job, and the products on our flea spray and ant killer pages arrive in their own containers.
Who May Spray
HSE’s rule for pesticide sprayers turns on birth date and on whether the spraying is a service: “If you were born after 31 December 1964 or you will be spraying as a commercial service, you must hold the appropriate Certificate of Competence National Proficiency Tests Council (NPTC) or Scottish Skills Testing Service (SSTS), unless you are under the direct and personal supervision of a person who holds such a certificate.” (HSE). For those born before that date and working on their own land, HSE says you “need to be able to demonstrate competence and show proof of appropriate training.”
The rule reaches the sale as well as the spraying. HSE’s agriculture guidance states that “Anyone who purchases a pesticide product must ensure that the end user holds a specified certificate.” and tells buyers to “Look for the MAFF, MAPP or HSE approval number on the label on the container.” (HSE). The sprayers on this page are sold to anyone; the pesticides that go in them are not, and a landlord buying both should read that as the honest position.
Insecticides used against pests in buildings are biocides rather than plant protection products, and HSE’s rule there is the product split: “members of the general public must not use professional or industrial use products” (HSE). A sprayer that can take a professional-use concentrate does not make its owner a professional user.
Where a Sprayer Does Not Help
When the listing cannot tell you what you are buying. The Solo 473D is listed as 10 litre in its title and 12 litre in its feature text. The Matabi is listed as 12L in its title and 16 L in its detail table. This page reports both figures for each and resolves neither; buy on the basis that the listing is uncertain.
Where the listing states no pump or no pressure. The Oregon lists neither; the Matabi lists a three-position regulator and no pump type. A pressure a listing does not state is a pressure this page does not state.
As a substitute for the product label. Nothing about the tank changes what the pesticide label permits — the area, the dose, the protection, or who may apply it.
What Decides the Choice
1. Tank capacity as listed
From 10 litres to 20. A larger tank is more weight on your back for longer; the Solo 425 is listed at 4.49 kg empty and the Oregon at 3.93 kg. Buy for the area you actually treat in one session.
2. Pump type as listed
Three listings state a pump type: diaphragm on both 10 litre Solos, piston on the Solo 425. Two state none. The comparison table says which, and says “not stated” where the listing is silent.
3. Pressure as listed
4 bar on the Solo 473D, 4 bar / 90 psi on the Solo 90psi, up to 90 psi on the Solo 425. The pesticide label, not the sprayer, decides what pressure the product should be applied at.
If a Sprayer Is Not the Answer
Use the product’s own container. Most consumer insecticides arrive ready to use. Our cockroach killers and flea spray pages compare them.
Bait instead of spraying. For ants and cockroaches the product class is different — see our ant killers page.
Have it applied by a certificate holder. Where the product you need is professional-use only, that is the arrangement HSE’s rule describes.
Using One
- Read the label on the product, not the sprayer. Dose, area, protection and who may apply it are all there and nowhere else.
- Check the approval number. HSE’s own instruction is to look for the MAFF, MAPP or HSE number on the container.
- Fill by the listing figure you have least reason to doubt. Where a listing gives two capacities, the smaller one is the safer basis for a dose calculation.
- Set pressure by the product label. The sprayer’s maximum is not a recommendation.
- Rinse and store as the label says. HSE tells users to keep pesticides in their original containers with the approved product labels; a sprayer left full is a container without one.
A job that needs a certificate holder?
Where the product is professional-use only, compare pest control providers near you — no fees, no commissions.