Comparison: Best Schultz Indoor Plant Food (Updated | Nov 11th)

Look at the N-P-K ratio to match the nutritional needs of your plants; most Schultz formulas use a 10-15-10 balance suitable for a wide range of species. Check the bottle size—8 oz provides better value for frequent watering, while 4 oz is handy for occasional use or travel. Also verify that the product is labeled for indoor use if you plan to feed houseplants.

Both share the same 10-15-10 N-P‑K ratio, but the SPF45170 offers double the volume, making it more cost‑effective for larger collections of plants. The smaller SPF45160 is easier to store and may be preferable for beginners who want to test the formula before committing to a larger bottle.

The two‑pack provides four ounces total, which is convenient for indoor gardeners who need a small, precise amount of fertilizer. Its “7 drops per quart” dosing system helps avoid over‑feeding, and the price is usually lower per ounce than buying a single larger bottle, making it a value‑focused option.

Yes, Schultz’s 10‑15‑10 formulas are marketed as universal, working well on flowers, vegetables, shrubs, and houseplants alike. The nutrient balance supports steady growth, but for specialized plants like African violets or cacti, consider the dedicated formulas that adjust the N‑P‑K ratio for optimal bloom or drought tolerance.

The African Violet Plus formula has a higher phosphorus (14) and lower potassium (9), which encourages more vibrant blooms in flowering plants like violets. It also uses the same 7‑drop dosing system, ensuring precise nutrient delivery without risking leaf burn.

Cactus Plus reduces nitrogen to 2 % while providing moderate phosphorus and potassium, matching the low‑nutrient environment cacti thrive in. This prevents excessive, soft growth and helps maintain the plant’s natural compact form, especially important for desert‑type species.

Miracle‑Gro’s indoor formula is designed specifically for container plants and includes a quick‑release nutrient blend that shows results within days. While it may be slightly more expensive per ounce than Schultz’s 8 oz bottles, the two‑bottle bundle offers convenience and a reliable performance for a wide range of houseplants.

The 1.5 lb (24 oz) bulk package delivers the lowest cost per ounce, ideal for gardeners with many plants or frequent feeding schedules. Smaller bottles are better for limited storage space or for testing the product on a few plants before buying in bulk. Consider your watering frequency and plant count to decide which size maximizes both convenience and savings.