Best Water Soluble Fertilizer for Indoor and Outdoor Plants

#1 · Best Overall

1. Miracle-Gro All Purpose Plant Food

• Weight: 1.5 lb
• Form: Powder

Best for: Mixed indoor and outdoor gardens.

Why it ranks #1: Its 24-8-16 formula is listed for indoor and outdoor plants, including houseplants, vegetables, flowers, roses, and trees.

A 24-8-16 formula that feeds indoor and outdoor plants, from houseplants and roses to vegetables and trees, makes this Miracle-Gro option a flexible choice across a mixed garden. Its water-soluble powder starts working instantly, offering a quick-feed routine for gardeners tending several plant types.

The broad plant list means one product can serve houseplants, flowers, vegetables, and trees rather than requiring a separate food for each. Its powder dissolves in water and starts working instantly, so feeding can be folded into watering when plants need a quick boost. Miracle-Gro says it will not burn plants when used as directed; leftover powder can be closed up and stored in a dry spot away from children and pets.

Skip it if you need equal nitrogen, phosphorus, and potassium; Jack's Classic 20-20-20 offers that balanced ratio.

Choose this for a mixed indoor-outdoor collection when quick, water-soluble feeding matters more than an equal NPK ratio. It covers many plant types, but follow directions and store leftover powder dry and away from children and pets.

Listed on Amazon as: Miracle-Gro Water Soluble All Purpose Plant Food, 1.5 lb.

#2 · Flexible Feeding

2. Jack's Classic 20-20-20

• Weight: 1.5 lb
• Form: Powder

Best for: Flexible root and foliar feeding.

Why it ranks #2: The balanced 20-20-20 powder supports indoor and outdoor plants and can be applied as root feed, foliar spray, or continuous feed.

Jack's Classic supports both root feeding and foliar application, giving gardeners two ways to deliver its balanced 20-20-20 formula. The water-soluble powder can also be used in a continuous-feed system, so it fits routines ranging from direct leaf spraying to ongoing irrigation-based feeding.

Mixing the measured powder with water creates a concentrate that can be applied to leaves or roots, rather than limiting feeding to one route. The listed continuous-feed compatibility also lets growers incorporate it into an established system. Its 20-20-20 analysis is associated with fast green-up and rapid leaf expansion, while the 1.5-pound tub provides a powder format for repeated mixing. Keep it stored in a cool, dry place away from heat and open flame.

Skip it if you want packet-based feeding without measuring; Miracle-Gro Watering Can Singles provides pre-measured portions.

This fits growers who want a balanced formula with root, foliar, and continuous-feed options. Choose it when measuring and mixing suits your workflow; those wanting ready-portioned doses should consider a packet format instead.

Listed on Amazon as: Jack's Classic 20-20-20 All Purpose Water-Soluble Fertilizer, 1.5lb

#3 · Micronutrient Blend

3. GS Plant Foods 20-20-20

• Weight: 3 lb
• Form: dry

Best for: Balanced nutrition with kelp.

Why it ranks #3: This 3-pound balanced 20-20-20 formula includes iron, manganese, copper, zinc, boron, molybdenum, and kelp.

A balanced 20-20-20 NPK formula combines with listed micronutrients and kelp in this GS Plant Foods water-soluble fertilizer. That nutrient profile serves indoor and outdoor plants, gardens, and turf, giving gardeners a broad-use option when they want more than the primary nutrients alone.

The formula lists iron, manganese, copper, zinc, boron, and molybdenum alongside nitrogen, available phosphate, and soluble potash, providing a wider stated nutrient profile than NPK alone. Kelp from Ascophyllum nodosum is also included, and the product is identified for indoor and outdoor plants, gardens, and turf. Together, those features make it suitable for varied growing areas, though the supplied details do not specify a mixing rate or application schedule.

Skip it if you need a listed mixing rate before buying; Jack's Classic 20-20-20 includes measured-powder mixing directions.

This suits gardeners seeking balanced NPK with listed micronutrients and kelp for varied indoor, outdoor, garden, or turf use. Check that its supplied directions meet your needs, since no mixing rate or schedule is provided here.

Listed on Amazon as: GS Plant Foods All Purpose Water Soluble 20-20-20 Fertilizer Balanced NPK Plant Food with Micronutrients, Contains Kelp (Ascophyllum nodosum) for Indoor & Outdoor Plants, Gardens & Turf (3 lbs)

#4 · Largest Package

4. Southern Ag PowerPak 5 lb

• Weight: 5 lb
• Form: Granules

Best for: Larger-volume balanced garden feeding.

Why it ranks #4: The 5-pound 20-20-20 formula includes chelated minor elements and is listed for flowers, vegetables, lawns, trees, and houseplants.

A 5-pound supply of balanced 20-20-20 fertilizer with chelated minor elements makes Southern Ag PowerPak a fit for gardeners feeding multiple plant types. Its listed uses span flowers, roses, vegetables, shrubs, trees, lawns, and houseplants, with water mixing supporting general application.

The 20-20-20 analysis supplies equal listed percentages of nitrogen, phosphorus, and potassium, while chelated minor elements add micronutrients to the formula. Southern Ag gives a general rate of two teaspoons per gallon and also lists spray or drench directions for specific applications. That gives the user a measured mixing routine across its named plant categories; the five-pound supply is suited to a broader feeding workload than a small container.

Skip it if you tend a few plants and want a smaller supply; Southern Ag PowerPak 20-20-20 in the 1-pound size is the same listed formula.

This is a practical match for gardeners feeding a range of plants and wanting a larger supply of balanced fertilizer with micronutrients. Its five-pound format is a consideration for small collections with limited use.

Listed on Amazon as: Southern Ag PowerPak 20-20-20 Water Soluble Fertilizer with micronutrients (5 LB)

#5

5. Pennington All Purpose 20-10-20

• Weight: 1.5 lb
• Form: Powder

Best for: Easy-scoop all-purpose feeding.

Why it ranks #5: Its 20-10-20 formula is listed for fruits, vegetables, and flowers, with a scoop and directions to apply every 7–14 days.

A wide-mouth jar and included measuring scoop make Pennington's water-soluble powder convenient to portion without messy scooping. The 20-10-20 formula is aimed at fruits, vegetables, and flowers, while its all-purpose positioning lets gardeners use one mix across varied plantings at the stated dilution.

The wide opening gives the scoop room to enter the jar, and the foam-sealed lid is specified to conserve freshness while keeping the mix dry and free-flowing. That combination supports repeated measuring between feedings rather than handling a clumped product. Pennington calls for feeding every 7–14 days or as needed, and lists use on fruits, vegetables, and flowers; dilute according to the label for the plants being fed.

Skip it if you want equal NPK percentages; Gardenwise 20-20-20 Water-Soluble Fertilizer has a balanced 20-20-20 analysis.

This suits gardeners who value a scoop-and-jar routine for feeding fruits, vegetables, and flowers on a 7–14-day schedule. Its 20-10-20 ratio is the boundary: choose another formula if equal NPK percentages are essential.

Listed on Amazon as: Pennington Water Soluble All Purpose Plant Food 20-10-20 1.5 LB

#6

6. Southern Ag PowerPak 1 lb

• Weight: 16 oz
• Form: Soluble Fertilizer

Best for: Compact balanced micronutrient blend.

Why it ranks #6: This 1-pound 20-20-20 option includes chelated minor elements and is listed for flowers, vegetables, shrubs, trees, lawns, and houseplants.

Southern Ag PowerPak pairs a balanced 20-20-20 analysis with chelated minor elements in a one-pound size. That compact supply offers the same listed broad plant applications as the brand's formula, making it relevant to gardeners wanting balanced nutrition without starting with a larger container.

The formula lists use on flowers, roses, vegetables, shrubs, trees, lawns, and houseplants, giving one mix a wide range of potential garden roles. Directions call for two teaspoons per gallon of water, which turns the soluble fertilizer into a measured watering solution. Its one-pound size is easier to match to a limited feeding workload than a larger supply, while the micronutrients complement the equal nitrogen, phosphorus, and potassium percentages.

Skip it if you feed extensive plantings and want more on hand; Southern Ag PowerPak 20-20-20 in the 5-pound size has the larger supply.

Choose this for a smaller collection needing a balanced formula with chelated minor elements across several plant types. The one-pound amount is the key boundary for gardeners managing lawns or extensive plantings.

Listed on Amazon as: Southern Ag PowerPak 20-20-20 Water Soluble Fertilizer with micronutrients (1 LB)

#7 · Pre-Measured Packets

7. Miracle-Gro Watering Can Singles

• Weight: 8 oz
• Form: SOLID

Best for: Pre-measured watering-can doses.

Why it ranks #7: The 24 pre-measured packets remove scoop measuring; one packet mixes with one gallon of water for in-ground and outdoor container plants.

Pre-measured packets remove the need to measure loose fertilizer, making Miracle-Gro Watering Can Singles a simple way to feed while watering. Each packet is intended for one gallon of water for in-ground and outdoor container plants, and the product is also listed for indoor use.

The single-dose format helps gardeners prepare a watering can without scooping powder or handling an open container, supporting a tidier routine during the growing season. The listed schedule is every one to two weeks, and the product can be used on flowers, vegetables, houseplants, roses, trees, and shrubs indoors or outdoors. Its packet approach trades flexible scoop-based measuring for a defined dose, so follow the stated application directions for the plants being fed.

Skip it if you need to adjust fertilizer amounts by the scoop; Miracle-Gro Water Soluble All Purpose Plant Food comes as powder.

Choose these packets for routine feeding when convenience and avoiding loose-fertilizer measuring matter. They suit a watering-can workflow across many plant types, but gardeners who need variable doses may prefer a scoop-measured powder.

Listed on Amazon as: Miracle-Gro Watering Can Singles All Purpose Plant Food, 24 Packets

#8

8. Gardenwise 20-20-20

• Weight: 8 oz
• Form: Granules, Powder

Best for: Experienced growers seeking balanced NPK.

Why it ranks #8: Its balanced 20-20-20 formula has separate listed rates for indoor plants, outdoor plants, and lawns, though the product recommends it for professionals.

A balanced 20-20-20 analysis gives Gardenwise equal nitrogen, phosphate, and potash, with directions spanning indoor plants, outdoor plants, and lawns. That broad application range can suit a practiced grower managing several settings, though the listing recommends the formula for professional gardeners and landscapers.

Separate mixing rates—1⁄2 teaspoon per gallon for indoor plants, 1 tablespoon per gallon outdoors, and 1 ounce per gallon for lawns—help adapt the same powder to different growing areas. The product also lists hydroponic and orchid use, plus flowers, shrubs, and container gardens, making it versatile for an experienced operator. Its 8-ounce size is a smaller supply than larger formats, so it may call for more frequent replenishment in extensive use.

Skip it if you are new to fertilizer mixing; Miracle-Gro Watering Can Singles All Purpose Plant Food provides pre-measured packets.

Consider this for an experienced gardener or landscaper who can follow its different indoor, outdoor, and lawn dilutions. Its broad use list is useful, but the professional-user recommendation makes it less suited to someone seeking a pre-measured routine.

Listed on Amazon as: Gardenwise 20-20-20 Water-Soluble Fertilizer – Powder for Liquid Plant Food for Indoor & Outdoor Plants, Orchids, Vegetables, Lawns, Flowers – 20 20 20 Fertilizer (0.5 lb~ 8 oz)

#9

9. Fertilome All Purpose 20-20-20

• Weight: 8 oz
• Form: Liquid

Best for: Frequent feeding for flowering plants.

Why it ranks #9: The 8-ounce 20-20-20 formula is suitable indoors and outdoors, with separate soil-drench and foliar-spray mixing directions.

Fertilome combines a 20-20-20 formula with soil-drench and foliar-spray application, giving flower growers two ways to feed. Its listed plant examples include geraniums, pansies, petunias, impatiens, annuals, perennials, and hanging baskets, indoors or outdoors.

The directions distinguish soil-drench mixing at one to two teaspoons per gallon from foliage feeding at one-quarter to one teaspoon per gallon, letting users tailor the solution to the application method. The product is described as supporting flower size, quantity, color vibrance, and continuous production. Its recommended frequency—every watering or every three to four days—means it suits a frequent-feeding routine rather than occasional monthly feeding.

Skip it if you prefer feeding every one to two weeks; Scotts Super Bloom lists a 7–14-day interval for blooming plants.

This fits flower growers who want both root-zone and foliar feeding options and can follow a frequent schedule. Consider the application frequency and separate dilution rates before choosing it for a lower-maintenance routine.

Listed on Amazon as: Fertilome (11728) All Purpose Water Soluble Plant Food 20-20-20, 8 oz

#10

10. Scotts Super Bloom

• Weight: 2.1 lb
• Form: Liquid

Best for: Outdoor flowering and fruiting plants.

Why it ranks #10: This water-soluble option has high phosphorus for outdoor flowers and fruiting plants, but its listed use is narrower than general-purpose formulas.

High phosphorus is the defining feature of Scotts Super Bloom, which targets blooming plants and fruiting growth rather than general-purpose feeding. Its water-soluble formula feeds instantly and is listed for outdoor flowers, fruiting plants, containers, and bed areas, with an application interval of one to two weeks.

The directions specify two teaspoons per gallon, applied to moist soil around the plant base, so gardeners have a defined preparation and placement routine. Feeding every 7–14 days gives blooming plants a recurring schedule, while the high-phosphorus formula is intended to help plants bloom. Scotts lists roses and all flowering plants among its uses and says it will not burn plants when used as directed; the stated setting is outdoor use.

Skip it if you need one fertilizer for indoor houseplants too; Miracle-Gro Water Soluble All Purpose Plant Food lists indoor and outdoor use.

Choose this for outdoor flowering or fruiting plants when a high-phosphorus feed and repeat schedule fit your routine. Its stated use centers on outdoor settings, so select an all-purpose indoor-and-outdoor formula for houseplants.

Listed on Amazon as: Scotts Super Bloom Water Soluble Plant Food, 2 lbs.