1000 m2 garden - how much fertilizer do you need?

    Same garden bed, two soil conditions - the difference is 30% more fertilizer. Enter the area, pick your plant type (lawn, vegetables, flowers, trees or universal) and soil fertility level. Get the dose per m2, total weight in kilograms, bag count and cost.

    A 1000 m2 lawn on medium-fertility soil needs about 70 g/m2 of NPK fertilizer - but the same area with poor sandy soil requires 30% more. Vegetables, flowers and trees each have different base doses ranging from 45 to 80 g/m2. Enter 1000 below with your plant type and soil condition to get the precise weight in kilograms and the number of 5 kg or 10 kg bags to purchase.

    Parameters

    Enter data for calculations

    Total area you want to fertilize

    Lawn = high N | Vegetables = high K | Flowers = high P | Universal = balanced

    If unsure, select Medium

    Universal NPK: $2-5/kg | Specialty: $5-10/kg

    Form progress0 / 3 fields

    💡 Fill in all required fields to unlock the calculate button

    Fertilizer calculator - the right dose for every plant

    Enter the area, select what you are growing and your soil condition. The calculator returns the fertilizer dose in g/m2, total weight, bag count and cost. A 100 m2 lawn on medium soil needs 7.0 kg of NPK fertilizer - but the same lawn on poor sandy soil needs 9.1 kg (+30%). That single variable changes your shopping list from 2 bags to 2 bags of 5 kg - same bag count, but almost no reserve left for the second application.

    How to use the fertilizer calculator - step by step

    1. Area (m2) - total area to fertilize. Measure length x width of the bed, lawn or garden section.
    2. Plant type - lawn (70 g/m2 base), vegetables (60), flowers (45), trees/shrubs (80) or universal (40). Each has a different NPK emphasis.
    3. Soil fertility - low (+30% dose), medium (standard) or high (-30% dose). If unsure, select medium.
    4. Price (optional) - enter your local fertilizer price for a cost estimate.
    5. Read the results - dose per m2, total kg, bag count (5 kg and 10 kg), and cost.

    Before and after - how soil fertility changes your dose

    BEFORE - Poor sandy soil

    Lawn 200 m2: 91 g/m2 = 18.2 kg

    Vegetables 50 m2: 78 g/m2 = 3.9 kg

    Flowers 30 m2: 59 g/m2 = 1.8 kg

    Total: 23.9 kg | ~$96 at $4/kg

    AFTER - Rich composted soil

    Lawn 200 m2: 49 g/m2 = 9.8 kg

    Vegetables 50 m2: 42 g/m2 = 2.1 kg

    Flowers 30 m2: 32 g/m2 = 1.0 kg

    Total: 12.9 kg | ~$52 at $4/kg

    Savings: Improving soil with compost over 2-3 years cuts fertilizer cost by 46% - from $96 to $52 per season. The compost itself costs $0 if you make it at home.

    Dose reference table

    Plant type Low soil Medium soil High soil Key nutrient
    Lawn 91 g/m2 70 g/m2 49 g/m2 Nitrogen (N) for green growth
    Vegetables 78 g/m2 60 g/m2 42 g/m2 Potassium (K) for fruiting
    Flowers 59 g/m2 45 g/m2 32 g/m2 Phosphorus (P) for blooming
    Trees/shrubs 104 g/m2 80 g/m2 56 g/m2 Balanced NPK for roots
    Universal 52 g/m2 40 g/m2 28 g/m2 NPK 15-15-15 balanced

    Practical examples

    Small lawn (80 m2, medium soil): 80 x 70 = 5,600 g = 5.6 kg. Buy 2 x 5 kg bags. Cost at $4/kg: $22.
    Vegetable garden (25 m2, low fertility): 25 x 78 = 1,950 g = 1.95 kg. Buy 1 x 5 kg bag (3 kg reserve for mid-season). Cost at $6/kg: $12.
    Flower bed (15 m2, high fertility): 15 x 32 = 480 g = 0.48 kg. A single 1 kg box covers two applications.
    Orchard (200 m2, medium soil): 200 x 80 = 16,000 g = 16.0 kg. Buy 2 x 10 kg bags. Cost at $3/kg (bulk): $48.
    Full garden (lawn 150 m2 + veg 30 m2 + flowers 20 m2, medium): Lawn 10.5 kg + veg 1.8 kg + flowers 0.9 kg = 13.2 kg total. Cost at $4/kg: $53.

    FAQ

    What does NPK mean on a fertilizer bag?
    N = Nitrogen (leaf growth, green colour), P = Phosphorus (roots, flowers, fruit), K = Potassium (overall health, disease resistance). The numbers like 15-15-15 show the percentage of each nutrient by weight. A 10 kg bag of 15-15-15 contains 1.5 kg of each.
    Can I over-fertilize?
    Yes, and it is a common mistake. Over-fertilizing causes root burn (brown, crispy leaf edges), excessive leaf growth at the expense of flowers/fruit, and nutrient runoff into waterways. The calculator gives the recommended dose - never exceed it. If in doubt, apply half the dose twice instead of the full amount once.
    When should I fertilize my lawn?
    Two key windows: spring (March-April) with a high-nitrogen fertilizer for green growth, and autumn (September-October) with a high-potassium fertilizer for root strength and winter hardiness. Avoid mid-summer fertilizing in hot, dry weather - the granules can scorch grass.
    How do I know my soil fertility level?
    The best method is a soil test kit ($10-20) or lab analysis ($30-50). Without testing: sandy soil is usually low, clay soil is often medium to high, soil that has received compost for 3+ years is typically high. A soil with visible earthworm activity is a good sign of fertility.
    Granular vs liquid fertilizer - which should I use?
    Granular releases slowly over 4-8 weeks - better for lawns and long-term feeding. Liquid is absorbed immediately - better for quick fixes and foliar feeding. For most home gardens, granular NPK is simpler and more cost-effective. The calculator doses apply to granular fertilizer.
    Is organic fertilizer better than chemical NPK?
    Both work. Organic (compost, manure, bone meal) improves soil structure over time but releases nutrients slowly. Chemical NPK delivers precise nutrients fast but does nothing for soil biology. Best approach: combine both - use compost as a base layer and supplement with targeted NPK where plants show deficiency.

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    Calculator verified by the LiczGrupa.pl team

    Content, formulas and results have been reviewed for accuracy and relevance by our team of specialists.

    Patryk Matyjasik

    Reviewed by: Patryk Matyjasik