6 Homemade Liquid Fertilizers For Tomatoes That Old Farmers Swear By

You’ve done everything right—good soil, plenty of sun, consistent water—but your tomato plants just seem to be sitting there, not quite thriving. Before you reach for a plastic bottle of mysterious blue crystals, consider what seasoned growers have known for generations. The best feeds often come from your own yard, not a store shelf.

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Why Homemade Feeds Beat Store-Bought Options

When you make your own fertilizer, you control the ingredients. There’s no mystery, no unpronounceable chemicals, just simple, effective nutrients derived from materials you might otherwise throw away. This approach saves money and reduces waste, turning kitchen scraps and yard clippings into black gold for your garden.

More importantly, homemade liquid feeds are often teeming with microbial life. Unlike sterile, synthetic fertilizers that offer a quick chemical hit, things like compost tea introduce beneficial bacteria and fungi to the soil. These microorganisms build soil structure, improve water retention, and help your plants access nutrients that are already present but locked away. You’re not just feeding the plant; you’re feeding the entire soil ecosystem.

Of course, there’s a tradeoff. Brewing your own fertilizer takes a little more time and thought than just mixing a powder with water. The nutrient content isn’t standardized, and some brews can get a bit fragrant. But the payoff is a resilient, living soil that supports healthier, more productive plants season after season.

Brewing Nutrient-Rich Compost Tea for Growth

Compost tea is the ultimate all-purpose tonic for your garden. Think of it as a liquid probiotic, delivering a broad spectrum of nutrients and beneficial microbes directly to your plant’s root zone. It’s less about a high-octane nutrient blast and more about enhancing the overall vitality of the soil and the plant.

Making a simple batch is easy. Take a few shovelfuls of your best, finished compost—the dark, earthy-smelling stuff—and place it in a porous bag, like an old pillowcase or burlap sack. Submerge the bag in a five-gallon bucket of non-chlorinated water (let tap water sit out for 24 hours to dissipate chlorine) and let it steep for a day or two, stirring occasionally.

The resulting liquid should be the color of weak tea. This brew is gentle enough to be used every couple of weeks throughout the growing season. It strengthens plant cell walls, improves nutrient uptake, and can even help suppress common fungal diseases. It’s the perfect feed for maintaining steady, vigorous growth from seedling to harvest.

Creating a Potent, Well-Aged Manure Tea

For a serious nitrogen boost, nothing beats manure tea. This is the old-timer’s secret for getting tomato plants to explode with leafy, green growth early in the season. The key, however, is to use well-aged manure from herbivores like chickens, rabbits, or cows. Fresh manure is far too "hot" and will burn your plant’s roots.

The process is identical to making compost tea. Put a few shovelfuls of crumbly, aged manure into a sack, steep it in a bucket of water for a few days, and wait for the water to turn a rich brown. If you don’t have your own livestock, bagged composted manure from a garden center works just fine.

Because it’s so rich in nitrogen, manure tea is best used during the first phase of growth, after transplanting and before the plant starts producing a lot of flowers. This encourages the development of a big, strong plant structure. Once flowers appear in earnest, taper off the manure tea to encourage the plant to shift its energy from making leaves to making fruit. Always dilute the final product to the color of weak tea before applying.

Harnessing Weeds for a Nitrogen-Rich Tea

Your most annoying weeds can become one of your most valuable resources. Many common weeds, like comfrey, stinging nettles, dandelions, and purslane, are "dynamic accumulators," meaning their deep taproots pull up valuable minerals from the subsoil. By fermenting them in water, you can unlock those nutrients for your tomatoes.

The method is simple, if a bit smelly. Chop up a bucketful of green, leafy weeds (before they go to seed), pack them down, and cover them with water. Put a lid loosely on the bucket—it will get fragrant—and let it sit in a corner of the yard for two to four weeks. The mixture will ferment and break down into a dark, nutrient-dense liquid.

This "weed tea" is another high-nitrogen feed, perfect for fueling early-season growth. Because it’s so concentrated, you must dilute it significantly before use, typically at a 1:10 ratio with water. It’s a fantastic, closed-loop system: you weed the garden, feed the weeds to a bucket, and then feed the resulting tea back to the garden.

Using Epsom Salt for Magnesium and Vigor

Epsom salt isn’t a complete fertilizer, but it’s a powerful supplement that provides two crucial secondary nutrients: magnesium and sulfur. Magnesium is a core component of chlorophyll, and a deficiency can lead to yellowing leaves and stunted growth. For tomatoes, sufficient magnesium is linked to better flower production and more robust fruit development.

Many soils, especially those that have been worked for years, can become deficient in magnesium. A simple drench of Epsom salt can correct this imbalance, resulting in darker green leaves and improved overall plant vigor. It helps the plant make better use of the primary nutrients—nitrogen, phosphorus, and potassium—that are already in the soil.

Use this as a targeted treatment, not a weekly feed. Dissolve one to two tablespoons of Epsom salt in a gallon of water and apply it as a soil drench around the base of your plants once a month during the peak growing season. Overuse can interfere with calcium uptake, so a little goes a long way. It’s a specific tool for a specific job.

Banana Peel Tea: A Simple Potassium Boost

As your tomato plants transition from growing leaves to producing fruit, their nutritional needs change. They require less nitrogen and much more potassium, which is essential for fruit development, flavor, and disease resistance. Banana peels, which you’d otherwise toss in the compost, are an excellent source of this vital nutrient.

Making this simple tea couldn’t be easier. Chop up the peels from three or four bananas and place them in a quart-sized jar. Fill the jar with water, seal it, and let it sit on a windowsill or countertop for three to seven days. The water will slowly leach the potassium and other trace minerals from the peels.

Strain the liquid and dilute it with an equal amount of water before applying it to the soil around your fruiting plants. This is a gentle, slow-acting boost that won’t overwhelm your plants. Start applying it when you see the first trusses of flowers appear and continue every few weeks through the harvest period.

Eggshell Water for Blossom End Rot Prevention

There’s nothing more frustrating than seeing a beautiful, nearly ripe tomato develop a dark, leathery patch on its bottom. This is blossom end rot, a physiological disorder caused by a lack of calcium available to the plant. While inconsistent watering is often the primary culprit, ensuring a steady supply of calcium is a crucial preventative measure.

Eggshells are almost pure calcium carbonate, but it takes a long time for them to break down in the soil. To make that calcium more readily available, you can create eggshell water. Thoroughly rinse and dry your eggshells, crush them into a coarse powder, and let them steep in a jar of water for a week or more. For a faster extraction, you can boil the crushed shells in water for 20 minutes.

This calcium-infused water provides a gentle, supplemental source of this critical nutrient. Think of it as prevention, not a cure. If you already see blossom end rot, this won’t fix the affected fruit, but it can help prevent it on new fruit that forms. The most important defense is still deep, consistent watering, but eggshell water provides an excellent nutritional safety net.

Application Tips and Feeding Schedule Guide

The single most important rule of fertilizing is to watch your plants, not the calendar. A healthy, dark green tomato plant that is growing well may not need anything at all. Yellowing leaves, slow growth, and a lack of blossoms are your cues to intervene.

That said, a general schedule can be a helpful guide. Think of it in two phases:

• Vegetative Phase (from transplant until first fruit set): The plant is building its "factory." Use a nitrogen-rich feed like a diluted manure or weed tea every 2-3 weeks to promote strong stem and leaf growth.
• Fruiting Phase (from first fruit set to end of season): The plant’s focus shifts to production. Switch to lower-nitrogen, higher-potassium and phosphorus feeds. Use compost tea for overall health and supplement with banana peel tea for potassium and Epsom salt for magnesium as needed.

Always water your plants thoroughly with plain water before applying any liquid fertilizer. Applying fertilizer to dry soil can scorch the roots. Feed in the early morning or evening to avoid the heat of the day, and apply the liquid directly to the soil around the base of the plant where the roots can access it immediately.

Ultimately, making your own liquid fertilizers is about more than just saving a few dollars; it’s about building a more resilient and self-sufficient garden. By using what you have, you close nutrient loops, foster a living soil, and develop a deeper understanding of what your plants truly need to thrive. The result is not only a better harvest but a healthier garden ecosystem for years to come.