Specs are compiled from manufacturer listings and verified buyer reviews and can change over time — please confirm the key details on the product page before buying.
Your plants’ growth stage decides which bat droppings (guano) you should buy. A high-nitrogen bag fuels leafy growth, but it can backfire when your tomatoes are about to flower. This guide ranks guano by its NPK ratio and form, so you can match the fertilizer to your garden’s growth stage.
I’m Rikta — the founder and writer behind Lawn Gear Lab. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
Match the guano’s NPK ratio to your plants’ growth stage and your preferred feeding schedule. That is exactly what this look at the bat droppings for fertilizer options delivers, with the good and the gritty of each one spelled out plainly.
Our Picks at a Glance
How To Choose The Best Bat Droppings For Fertilizer
Start by identifying your plants’ current growth stage. A fertilizer’s NPK numbers tell you the ratio of nitrogen (N), phosphorus (P), and potassium (K) inside. Nitrogen is the engine for leaves and stems. Phosphorus is what drives flowers, fruit, and roots. Feeding the wrong NPK balance can produce lush foliage but few flowers or fruits.
Match the NPK to the growth stage
Look for a higher first number (like 7-3-1) when your plants are young and putting on vegetative growth. That extra nitrogen keeps them lush and vigorous. When buds and fruit start to form, you want the middle number to jump up, so a blend with a higher phosphorus content (like 0-0.5-0.7 or a specific 1-12-0) helps push energy into blooms.
Liquid vs. dry granules
Liquid fertilizers work fast—just mix them into your watering can for a regular feeding schedule. Dry guano granules break down slowly, feeding the soil for weeks, which fits a top-dressing routine. Choose liquid for fast absorption or granules for slow, steady release.
Quick Comparison
| Model | Best For | Form | NPK Ratio | Size | Amazon |
|---|---|---|---|---|---|
| Fox Farm Big Bloom★ Best Overall | All-stage liquid feeding | Liquid | 0-0.5-0.7 | 1 Pint | Amazon |
| FoxFarm Happy Frog Cavern CultureBloom Booster | Bud & flower development | Powder | 1-12-0 | 4 lb | Amazon |
| Dr. Earth Pure & Natural Bat GuanoGrowth Power | Vegetative growth | Powder | 7-3-1 | 1.5 lb | Amazon |
| Roots Organics Terp Tea Grow | Heavy-feeding gardens | Dry | 7-1-1 | 3 lb | Amazon |
| Worm Castings Tea Plant Juice | Soil health & compost | Liquid | 0-0.6-0.5 | 1 Gallon | Amazon |
| Roots Organics Nitro Bat Guano | Nitrogen-rich feeding | Granules | — | 9 lb | Amazon |
| Hydrofarm Super Bat Budswel | Strong, multiple blooms | Liquid | — | 1 Gallon | Amazon |
| Down To Earth Organic Bat Guano | High-nitrogen plant food | Granules | 7-3-1 | 10 lb | Amazon |
In-Depth Reviews
1. Fox Farm Big Bloom Liquid Plant Food
Our pick — over 4.5★ from 13,000+ verified ratings; the strongest balance of quality and price.
The liquid workhorse that feeds every stage of your garden without fuss.
This is the crowd favorite — 4.7 stars across 13,000+ owners — and it earns that reputation by being the most forgiving fertilizer on this list. The NPK blend of 0-0.5-0.7 is gentle enough that it can be used every other watering, making it nearly impossible to burn your plants even if you get heavy-handed with the bottle.
It combines earthworm castings and bat guano into a liquid form that plants take up almost immediately. For best results, you mix 4 tablespoons (60 mL) into every gallon (4L) of water. That low-nutrient profile is a feature, not a flaw: it boosts root development and supports blooms throughout the whole season, so you never have to switch products when your plants move from leafy growth to fruiting.
The one quirk owners run into is that the concentrate settles, so you will need to shake the bottle frequently while mixing. The gentle 0-0.5-0.7 ratio supports every growth stage without the risk of nutrient burn. As owners put it: “Great product. Easy to use. And effective.”
What makes it click
- Gentle 0-0.5-0.7 ratio prevents nutrient burn
- Versatile enough for flowers, veggies, and houseplants
- Easy to apply with hose-end sprayer or drip irrigation
Where it will test you
- Concentrate settles, requiring frequent shaking
- Low NPK means it works best as part of a feeding routine
The pick for: Gardeners who want one simple liquid that safely feeds everything they grow.
Think twice if: You want a strong, single-dose bloom booster — this spreads its support across all stages.
2. FoxFarm Happy Frog Cavern Culture Bat Guano
The targeted phosphorus punch for gardeners who live for the flowering phase.
If you want to push energy into buds and blooms, the 1-12-0 ratio in this 4 lb powder is loaded in exactly the right place. That high middle number — the phosphorus — is what your plants crave when forming flowers and fruit. It pairs bat guano with seabird guano and rock phosphate to deliver a concentrated bloom kick that the standard all-purpose feeds simply cannot match.
Mix 2 tablespoons per gallon of water, or work it into the soil as a top-dressing. Owners are clear that blooming benefits are the standout — it is the thing mentioned most by a wide margin — and it is effective enough that some use it to activate their compost piles as well. It is an established formula from a brand that has been crafting organic soil mixes since 1984, so you are getting a tested product, not an experiment.
The trade-off is that this is a single-purpose tool. Do not reach for it during the leafy growth stage or you will miss the nitrogen your plants need. But when flowers are on the way, this powder delivers. “Plants loved the food,” as buyers report. “Gave me great results.”
The blooming payoff
- High phosphorus ratio targets bud and flower development
- Works as top-dressing or mixed into soil
- Backed by a trusted brand since 1984
The fit check
- Lacks nitrogen for the vegetative growth stage
- Powder form requires thorough watering after application
Grab this for: Gardeners focused on harvest quality and bigger, more plentiful blooms.
Look elsewhere if: You are still in the seedling and leafy-growth phase — you want nitrogen, not phosphorus.
3. Dr. Earth Pure & Natural Bat Guano
A little bag with a serious nitrogen kick for fast, leafy green growth.
This 1.5 lb bag is surprisingly mighty. The 7-3-1 NPK ratio is heavy on nitrogen, which makes it a go-to for pushing out vigorous vegetative growth. It feeds 12 five-gallon plants for up to 2 months, so a single bag goes a long way despite its small footprint. Effectiveness is the #1 thing owners praise — the reviews pages are full of stories about plants that “tripled in size” after a feeding.
This formula is safe for people and pets and made in the USA from sustainable ingredients—important if you grow edibles. The catch is the smell: some owners mention it is odorless, others call it “horrible.” Test it outside first if you work in a closed garage or shed.
Keep in mind that you should not overuse it — a little goes far, and too much can tip your soil’s balance. For a fast-acting nitrogen boost that disappears into your watering routine, this small bag delivers results that defy its size.
The growth upside
- High 7-3-1 nitrogen fuels leafy, vigorous growth
- Feeds 12 five-gallon plants for up to 2 months
- People and pet safe formula
The honest caveat
- Odor is polarizing — some bags smell strong
- Small bag size may not suit large gardens
Reach for this when: Your plants are in a growth spurt and need a fast, effective nitrogen boost.
skip it if: You are growing in a tight indoor space and are sensitive to strong smells — the scent is genuinely unpredictable.
4. Roots Organics Terp Tea Grow
The micronized grow feed that adds living biology to your soil, not just nutrients.
This 3 lb dry fertilizer goes beyond simple feeding. The 7-1-1 NPK is sourced from bat guano, fish bone meal, kelp meal, and chicken manure, but the real story is what is alive inside the bag. It contains beneficial bacteria like Bacillus subtilis and mycorrhizal fungi strains, which are the microorganisms that help roots access nutrients more efficiently. This is a soil-restoring feed, not just a plant snack.
You can use it as a base nutrition or a supplement, and it shines when brewed into a tea or applied as a top dressing. The micronized texture means it breaks down readily in water, and owners note there is no smell when using it — a real difference from some raw guano products. Quality is the most-praised aspect here, with plant growth and the nutritious profile close behind.
The one thing to plan for: it is a nitrogen-focused grow formula, so you will want to pair it with a bloom-specific feed when your plants start flowering. Think of this as the leafy-stage foundation in a two-part system.
The biology boost
- Contains beneficial bacteria and mycorrhizal fungi
- No smell when brewed or applied
- Versatile as top dressing, tea, or soil amendment
The pairing need
- Nitrogen-heavy 7-1-1 is not for the flowering stage
- Smaller 3 lb size if you have a huge garden
Choose this for: Gardeners who want to feed the soil food web, not just pump nutrients into leaves.
Not the one if: You want a single all-purpose product — this is a grow-stage formula that expects a bloom partner later.
5. Worm Castings Tea Plant Juice with Bat and Seabird Guanos
A gallon of concentrated soil medicine that supercharges your compost and your plants.
This is not just a guano fertilizer; it is a full soil-health program in a jug. The 0-0.6-0.5 blend combines bat and seabird guanos with worm castings, kelp meal, and humic acid. The maker claims it has a high concentration of worm castings, which gives it a highly dense quantity of microbes that break down organic matter and free up minerals for your plants.
Plant health is the clear theme across owner feedback — it is the most-mentioned aspect for good reason. Gardeners report fuller plants within a week of use, and the formula doubles as a compost activator to speed up decomposition. One bottle reportedly lasted a whole season for 5+ plants, which is impressive value for a concentrate. The NPK is gentle, so it works as a root drench or a foliar spray without the risk of burning.
It does have a smell, though most say it is tolerable compared to raw guano. The bigger consideration is that the nitrogen content is low, so heavy-feeding plants in their leafy stage may still want a dedicated grow feed alongside this.
Why soil loves it
- Dense microbes improve soil health and nutrient uptake
- Works as a compost activator
- One gallon concentrate lasts a long season
What to expect
- Noticeable odor, though tolerable to most
- Low NPK needs a grow feed for heavy feeders
Perfect for: Composters and organic gardeners who care as much about the soil as the harvest.
Pass on this if: You need a strong, simple nitrogen fix — this is a balanced soil restorer, not a growth bomb.
6. Roots Organics Nitro Bat Guano Fertilizer
A big 9 lb bag of bat guano that leans hard into nitrogen-rich growth.
This is the bag for gardeners who know exactly what they want: a high-nitrogen guano, processed and sifted so it is easy to work with. The 9-pound size is the real draw here — it is enough to feed a serious garden patch through multiple growth cycles, which is why it is the pick for anyone tired of reordering tiny bags every month.
The formula is an excellent source of nitrogen, phosphorus, and calcium, and it is harvested with bat-friendly methods, which is a nice ethical touch. Enthusiasts are direct in their praise, calling it “the best organic fertilizer on the market” and “the best form of organic fertilizer I’ve ever used.” That enthusiasm is echoed across hundreds of verified buyer reviews.
The granules are slower to break down than a liquid, so you need to plan ahead with this one. Work it into the soil before planting or as a top-dressing early in the season. It is a grow-stage tool, so keep your bloom feed handy for when flowers start forming.
The big-bag edge
- Large 9 lb quantity suits extended feeding
- Sifted for easy mixing and application
- Harvested with bat-friendly methods
Plan for this
- Granule form needs time to break down in soil
- Nitrogen focus means it is not a bloom booster
Best for: Gardeners with large plots who want a reliable, big-volume nitrogen source for the vegetative stage.
Consider another if: You have a few houseplants and need quick results — this is a slow-release soil builder, not an instant tea.
7. Hydrofarm Super Bat Budswel Organic Liquid Nutrient
The liquid bloom finisher that gardeners have trusted since the late ’80s.
Here is a bloom booster with serious staying power — some veterans report using this formula since 1988. HUBSWEL is a high-phosphorus mix of bat and seabird guano plus earthworm castings, and it is designed for one job: producing strong, multiple blooms in fruiting and flowering plants. It works in both soil and hydroponic setups, which makes it unusually flexible.
The 1-gallon jug mixes at a 1:100 ratio, so it stretches a long way. Owners consistently report improved resin production and deeper color in the final weeks of flowering. Plant performance is the most-praised aspect, and the formula draws particular praise for being odorless — a welcome change from raw guano powders. It has no expiration date, so you can keep it on the shelf between seasons.
The catch is that it is a finisher, not a grow feed. Used too early, you will not get the leafy structure you need. But when buds are setting, this liquid is what pushes them over the line.
The bloom payoff
- High phosphorus targets strong bud and flower development
- Odorless liquid formula
- Works in soil and hydroponics
The timing demand
- For the flowering phase only — not a veg feed
- Liquid settles, so shaking is required
Reach for it during: The final stretch of flowering when you want fuller buds, richer aroma, and denser resin.
Not for: The vegetative stage or gardeners who want one bottle for the whole season.
8. Down To Earth Organic Bat Guano
The 10 lb budget bag that proves raw guano does not need to be fancy to work.
This is the value pick for a reason: a full 10-pound bag with a solid 7-3-1 nitrogen-focused ratio for a budget-friendly price. It is straightforward, all-natural, and manufactured in the United States. If you know you want high-nitrogen bat guano and want the most pounds per dollar, this is the one to beat.
Enthusiasts use it in “Supersoil” recipes and swear by its performance, noting it compares favorably with pricier brands. The reviews pages sum it up with a memorable line: “This literally smells like bat turd because it’s literally bat turd. My plants adore it.” That is the trade-off in one sentence — it is authentic, and it works, but the smell is real.
One buyer did report their 10 lb bag came up 2 lbs short, which is worth keeping in mind if you are mixing a precise soil recipe. But for pure, no-frills nitrogen guano at this size, it is a hard option to overlook.
The value case
- Large 10 lb bag offers the best volume for the cost
- Solid 7-3-1 NPK for strong vegetative growth
- Made in the USA
The reality check
- Strong, authentic guano odor
- Weight can occasionally run short of the label
The budget pick for: Growers who want maximum nitrogen guano per dollar and do not mind working outside.
Weigh the trade-off: The smell is unmistakable, so if that bothers you, a processed liquid is the gentler route.
Understanding the Specs
NPK Ratio
The three numbers on any fertilizer bag tell you the percentage of nitrogen, phosphorus, and potassium. Nitrogen (the first number) drives leafy green growth. Phosphorus (the middle number) powers flowers, fruit, and roots. Potassium (the last number) supports overall plant health and disease resistance. A 7-3-1 guano is a growth feed; a 1-12-0 blend is a bloom feed.
Liquid vs. Granular Form
Liquid fertilizers are absorbed quickly, so you see results in days, but they wash through the soil faster and need reapplication. Dry granules break down slowly, feeding the soil food web over weeks. Your choice hinges on whether you prefer quick, hands-on feeding or a low-maintenance soil amendment.
FAQ
What is the difference between high-nitrogen and high-phosphorus bat guano?
Can I use bat guano on all my plants?
How often should I apply bat guano fertilizer?
Does bat guano smell bad?
How much bat guano should I mix per gallon of water?
Is bat guano better than worm castings?
Can I use bat guano to activate my compost pile?
Should I use liquid or granular bat guano?
What does NPK stand for on a guano bag?
How long does a bag of bat guano last?
Final Thoughts: The Verdict
For the majority of shoppers, the bat droppings for fertilizer winner is the Fox Farm Big Bloom because its gentle 0-0.5-0.7 liquid formula is safe for every growth stage and every type of plant you grow. If you want a targeted phosphorus boost for flowering and fruiting, grab the FoxFarm Happy Frog Cavern Culture with its powerful 1-12-0 blend. And for a budget-friendly nitrogen source that feeds a large garden while staying affordable, reach for the Down To Earth Organic Bat Guano in the big 10 lb bag.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of August 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
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