Can You Mix Fertilizers? Check the Exact Products First
Decision details
Fits if: Growers holding several products at home (foliar, NPK, AB, EM1, wood vinegar, pesticides) wanting to save time with one spray run.
Main drawback: Without confirmation for the exact products and method, a mix can make it harder to identify the cause if the result is unexpected.
Compare: full product names and front/back labels; crop and stage; application method; label rates and intervals; final water volume; written answer about the combination.
In this guide
[Reviewed: 12 October 2026]
Short answer: do not mix until that exact combination is confirmed
“Can foliar NPK be mixed with a product containing microbes such as EM1?” and “Can a fertilizer blend, Silmaxz Potash and Faterra go in one tank?” concern specific commercial products. Broad product names alone cannot answer either question. Check both labels and ask the seller or manufacturer to confirm the combination for your crop and intended method. If it is not confirmed, do not put the products in the same tank; follow each label separately.
What to verify before mixing
For each product, note four things: its full label name and formulation; your crop and its stage; whether you plan a foliar spray, soil drench or AB system; and the label’s rate, order and warnings. Do not use a broad term such as “NPK”, “foliar” or “microbe” as proof of compatibility. A rate for one product is not a combined rate.
| Grower question | What can the product names establish? | Information to send | Temporary action |
|---|---|---|---|
| Foliar NPK + a product containing microbes such as EM1 | Not enough to determine compatibility; the question does not identify formulations or method. | Exact names and front/back label photos for both products, crop/stage, method and label rates. | Do not tank-mix without product-specific confirmation. |
| Fertilizer blend + Silmaxz Potash + Faterra | Trade names alone do not show formulation, rate or mixing directions. | Full labels for all three, final water volume, crop/stage and application method. | Ask the seller/manufacturer for written confirmation and rates; otherwise use separately as labelled. |
| AB fertilizer + an additive | Do not transfer one formulation's example to another product or system. | A/B brand and formulation, additive, system and water volume. | Follow the AB set's instructions; add another product only if specific directions allow it. |
Request worksheet: copy and send to the seller
I want to check this combination before use. Crop and stage: ____. Method (foliar spray / soil drench / AB system): ____. Product 1 — exact name: ____; front/back label photos: attached; label directions and rate: ____. Product 2 — exact name: ____; front/back label photos: attached; label directions and rate: ____. Final water volume and tank size: ____. Do the manufacturer or labels confirm this combination for this crop and method? If yes, please state the confirmed order and rate. If it cannot be confirmed, I will use the products separately as labelled.
Ask for an answer tied to the exact products, not “usually fine”. If the labels conflict or there is no confirmation, stop before mixing and follow each product’s directions separately. Do not invent a gap of several days: use the label interval or ask the seller/manufacturer.
One AB example — not a universal rate
One UPM guide shows 100 ml of stock solution A and 100 ml of stock solution B added to 10 L of water for the formulation described there. That is a specific example, not a formula for every AB product or permission to add other products. Follow the instructions for your own set; UPM also notes that EC should be measured because formulations and water differ [source]. For broader nutrient-management principles, the Department of Agriculture sets out right source, rate, time and place [source].
Send a question that can be answered
Use the worksheet above with the product seller. Betulkex does not certify technical compatibility on a manufacturer’s behalf. If you are buying a GrowEasy product, ask the seller whether it is included in the BETUL10 first-order offer before paying [source].
For a GrowEasy NPK supply enquiry, send the product name, pack size, quantity and postcode. Availability of the exact product is unconfirmed [source]. Refer mixing compatibility to the product labels or manufacturer.
Frequently asked questions
Can I mix foliar NPK with a product containing microbes such as EM1?
It depends on the exact products, both labels and the application method. Do not infer compatibility because one product is called foliar or NPK. Send front and back label photos and the intended method to the seller or manufacturer; mix only if that combination is confirmed for that use. Otherwise follow each label separately.
Can AB fertilizer be mixed with other things?
One UPM example combines 100 ml of stock solution A and 100 ml of stock solution B in 10 L of water; do not treat that as a rate for other formulations [source]. For additives, check all labels and obtain confirmation for your product and system before mixing.
Can EM1 be mixed with fertilizer sprays?
The evidence referenced here does not establish whether a specific EM1 product is compatible with a specific foliar NPK. Check both labels or ask the manufacturer or seller. If there is no product-specific answer, do not combine them in one tank; use each as directed.
One tank saves time — what is the real risk?
The risk is acting without evidence for those products, crop and method, then having trouble identifying which product caused a response. Do not invent a universal gap: follow the label interval or ask the manufacturer or seller to confirm it.