A 1:100 dilution ratio means 1 part fertilizer concentrate mixed with 100 parts water. For example, if you have 1 gallon (3,785 mL) of water, you would add approximately 37.85 mL of liquid fertilizer concentrate. This is one of the most common ratios for regular plant feeding and is widely used for vegetables, flowers, and houseplants during the growing season.

Use the calculator above! Simply enter your water volume (e.g., 1 gallon), set your target dilution ratio (e.g., 1:100), and the tool instantly tells you how much fertilizer concentrate to add. For manual calculation: Fertilizer amount = Water volume ÷ Ratio number. With 1 gallon (3,785 mL) and a 1:100 ratio, you get 3,785 ÷ 100 = 37.85 mL. Always measure carefully for consistent results.

Seedlings and young plants have delicate root systems and require weaker solutions—typically 1:400 to 1:500 (or even weaker). Mature, actively growing plants can handle stronger feeds, usually 1:100 to 1:200. Heavy feeders like tomatoes and peppers may benefit from 1:50 to 1:100 during peak fruiting. Always start with a weaker solution and observe plant response before increasing concentration. Over-fertilization can cause fertilizer burn and root damage.

Absolutely! Foliar feeding typically requires more diluted solutions than root feeding, usually in the range of 1:400 to 1:800. The calculator works perfectly for foliar applications—just enter your sprayer volume and the recommended foliar ratio from your fertilizer label. Since nutrients are absorbed through leaf stomata, weaker concentrations prevent leaf burn while still delivering effective nutrition.

Water-based dilution (used by this calculator by default) means 1 part fertilizer added to X parts water—the most common method in gardening. Total-solution-based dilution means the fertilizer makes up 1 part of X total parts in the final solution. For weak dilutions like 1:100, the difference is negligible (about 1%). For stronger mixes like 1:10, water-based gives 100mL fertilizer per 1,000mL water (1,100mL total), while total-solution would give ~91mL fertilizer + 909mL water. Most fertilizer labels use water-based ratios unless stated otherwise.

Dilution ratio directly affects your nutrient solution's electrical conductivity (EC) and parts per million (PPM). A stronger solution (lower ratio number like 1:50) produces higher EC/PPM values. For hydroponics, target EC ranges vary by crop—leafy greens typically need 1.0–1.8 EC, while fruiting crops need 2.0–3.5 EC. Use an EC meter alongside this calculator to dial in your perfect concentration. Remember that different fertilizer brands have different EC contributions at the same dilution ratio.

Several factors can cause fertilizer burn despite correct dilution: 1) Environmental stress—plants under heat/drought stress absorb nutrients differently. 2) Accumulation—salts can build up in soil/pots over multiple feedings. 3) Dry soil—fertilizing dry root zones increases burn risk; always pre-moisten. 4) Product concentration—some fertilizers are more concentrated than typical. 5) Application frequency—feeding too often. Solution: flush with plain water, reduce to half-strength (double the ratio number), and ensure good drainage.