What It Is
In the early part of the season—when everything’s just starting to stretch and grow—I use a simple, no-fuss fertilizer mix that gives my plants a healthy boost and helps keep pest pressure down. It’s a combo of Hi-Brix Molasses and fish & seaweed fertilizer.
For years, I only used fish and seaweed fertilizer. But after digging into some research on brix (basically the sugar level in a plant's sap), I started adding Hi-Brix Molasses to help defend my plants—especially against cucumber beetles, which are my #1 garden pest. Aphids too, but cucumber beetles are the real bullies here.
Hi-Brix Molasses is made from plant sugars and is known for feeding beneficial soil microbes and supporting overall plant health. The fish and seaweed fertilizer brings a lot to the table too—fish emulsion is high in nitrogen, which helps fuel lush, green, leafy growth during the early stages, while the seaweed adds cytokinins and other natural plant hormones that encourage root development, flower production, and overall stress resilience. The fish & seaweed fertilizer (I use Neptune’s Harvest) delivers nitrogen for leafy growth and natural hormones that support root development and help plants handle stress. Together, they make a great early-season spray for young plants.
Why I Use It (and Why It Works)
The Role of Fish & Seaweed Fertilizer
Fish and seaweed fertilizer plays a major role in this mix. Here’s why it works:
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Natural nitrogen boost. Fish emulsion is high in nitrogen, which helps fuel lush, green, leafy growth during the early stages—exactly what young plants need.
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Hormonal support. Seaweed provides natural plant hormones like cytokinins and auxins, which help stimulate root growth and support strong, healthy development.
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Stress resilience. Those same hormones also help plants bounce back from heat, wind, or transplant shock.
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Long-term strength. A strong start leads to sturdier stems and better blooms later on.
I’ve used this combo on all kinds of flowers, and it consistently gives them a solid foundation to thrive.
What Is Brix?
Brix (°Bx) is a measure of the sugar content in plant sap. It reflects the concentration of dissolved sugars, amino acids, and nutrients within the plant. Higher brix levels are typically a sign of better nutrient uptake and photosynthetic activity, which leads to stronger, more resilient growth. Gardeners sometimes use a tool called a refractometer to measure brix levels as a way to monitor plant health.
Higher brix = stronger, healthier plants. Lower brix = plants that are more vulnerable to stress, disease, and pests.
Here’s why it matters:
The Role of Hi-Brix Molasses
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Raises brix levels. Higher sugar content in plant sap can help deter pests like cucumber beetles and aphids.
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Feeds soil microbes. The carbohydrates in molasses serve as a food source for beneficial bacteria and fungi in the soil, which play a crucial role in nutrient cycling and overall plant health.
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Supports energy for growth. The sugars in Hi-Brix Molasses act as an energy source that can help plants recover from stress, including transplant shock.
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Versatile use. Molasses can be used in watering solutions, compost teas, or hydroponic systems.
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Pests don’t like high-brix plants. Aphids, whiteflies, cucumber beetles—they’re drawn to plants with low brix levels because it’s easier for them to digest. When sugar levels go up, it can actually make the sap harder or even toxic for them to process.
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High brix is a sign of good nutrition. It usually means your plant is getting the minerals it needs and photosynthesizing efficiently—which shows up as strong growth and fewer problems.
So when I add molasses to my spray routine, I’m essentially helping the plant build resilience from the inside out.
Here’s the recipe I use:
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2 tablespoons Hi-Brix Molasses
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2 tablespoons fish & seaweed fertilizer
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Mix into 1 gallon of water
I apply it as a foliar spray using a backpack sprayer, but a watering can works fine for smaller areas. Spray early in the morning or later in the evening—just avoid hot, sunny parts of the day.
Repeat every 7–10 days while your plants are still small and growing. Once they start blooming, stop spraying. Molasses is sugary, and sugary sprays during bloom can attract ants, mess with pollinators, or even cause mildew if it’s humid. Plus, for cut flowers, the last thing you want is sticky residue on delicate petals.
By the time the plants are blooming, they should be strong enough to keep growing without help.
You can find both ingredients online or at your local garden center. I’ve included links to the exact products I use at the bottom of this post.
How to Apply It
Foliar Spray vs. Soil Drench
Foliar sprays are absorbed directly through the leaves—plants take in nutrients through tiny pores called stomata. This makes foliar feeding a fast and effective way to deliver nutrients, especially during the early stages of growth when plants are developing quickly. It’s also helpful when soil conditions aren't ideal, since you’re bypassing the roots and delivering nutrients straight to where they’re needed.
That said, this mix can also be applied as a soil drench. Feeding the soil supports microbial activity and root health, especially if you're working to build up your garden beds long-term. I like to do a bit of both early in the season, but focus mainly on foliar spraying for quick uptake when the plants are young.
This mix has become a regular part of my garden rhythm. It’s easy, affordable, and helps me get ahead of pests before they ever become a real problem. Whether you’re growing sweet peas, dahlias, snapdragons, or zinnias—it’s a solid tool to support early growth and stronger plants from the start.
Amazon Links:
(These are affiliate links, which means I may earn a small commission if you make a purchase—at no extra cost to you. Thanks for supporting my garden!)
1 comment
Thanks so much