Below 7 is acidic; above 7 is alkaline. Most home garden plants prefer soil that's a little on the acidic side, around 6.5. Exceptions include potatoes and rhododendrons, which thrive in 5 or 5.5
Soil acidity or alkalinity directly affects plant growth. If a soil is too sour or too sweet, plants cannot take up nutrients like nitrogen (N), phosphorus (P) and potassium (K).
Below is the Ideal pH levels for your Garden(s).
Ideal pH Levels for Vegetables :
Vegetable - Ideal pH:
Artichoke.. 6.5 - 7.5
Asparagus.. 6.0 - 8.0
Beans.. 6.0 - 7.5
Beet Root.. 6.0 - 7.5
Broccoli.. 6.0 - 7.0
Brussel Sprouts.. 6.0 - 7.5
Cabbage.. 6.0 - 7.5
Carrot.. 5.5 - 7.0
Cauliflower.. 5.5 - 7.5
Celery.. 6.0 - 7.0
Chicory.. 6.0 - 6.5
Chinese Cabbage.. 6.0 - 7.5
Corn.. 5.5 - 7.0
Cress.. 6.0 - 7.0
Cucumber.. 5.5 - 7.5
Garlic.. 5.5 - 7.5
Horseradish.. 6.0 - 7.0
Kale.. 6.0 - 7.5
Kohlrabi.. 6.0 - 7.5
Leek.. 6.0 - 8.0
Lentil.. 5.5 - 7.0
Lettuce.. 6.0 - 7.0
Mushroom.. 6.5 - 7.5
Mustard.. 6.0 - 7.5
Onion.. 6.0 - 7.0
Parsnip.. 5.5 - 7.5
Pea.. 6.0 - 7.5
Peanut.. 5.0 - 6.5
Pepper.. 5.5 - 7.0
Potato.. 4.5 - 6.0
Potato- Sweet.. 5.5 - 6.0
Pumpkin.. 5.5 - 7.5
Radish.. 6.0 - 7.0
Rhubarb.. 5.5 - 7.0
Shallot.. 5.5 - 7.0
Soybean.. 5.5 - 6.5
Spinach.. 6.0 - 7.5
Tomato.. 5.5 - 7.5
Turnip.. 5.5 - 7.0
Water Cress.. 5.0 - 8.0
Watermelon.. 5.5 - 6.5
Ideal pH Levels for Flowers :
Flower - Ideal pH:
Ageratum 6.0 - 7.5
Alyssum 6.0 - 7.5
Aster 5.5 - 7.5
Azalea 4.5 - 6.0
Calendula 5.5 - 7.0
Candytuft 6.0 - 7.5
Canation 6.0 - 7.5
Celosia 6.0 - 7.0
Crysanthemum 6.0 - 7.0
Columbine 6.0 - 7.0
Coreopsis 5.0 - 6.0
Cosmos 5.0 - 8.0
Crocus 6.0 - 8.0
Dafodil 6.0 - 6.5
Dahlia 6.0 - 7.5
Day Lily 6.0 - 8.0
Delphinium 6.0 - 7.5
Dianthus 6.0 - 7.5
Forget-Me-Not 6.0 - 7.0
Forsythia 6.0 - 8.0
Foxglove 6.0 - 7.5
Gladiola 6.0 - 7.0
Gypsophilia 6.0 - 7.5
Holly 5.0 - 6.5
Hyacinth 6.5 - 7.5
Iris 5.0 - 6.5
Lavendar 6.5 - 7.5
Lilac 6.0 - 7.5
Marigold 5.5 - 7.0
Morning Glory 6.0 - 7.5
Nasturtium 5.5 - 7.5
Pansy 5.5 - 7.0
Petunia 6.0 - 7.5
Pinks 6.0 - 7.5
Poppy 6.0 - 7.5
Portulaca 5.5 - 7.5
Primrose 5.5 - 6.5
Roses 5.5 - 7.0
Salvia 6.0 - 7.5
Snapdragon 5.5 - 7.0
Sunflower 5.0 - 7.0
Sweet Pea 6.0 - 7.5
Sweet William 6.0 - 7.5
Tulip 6.0 - 7.0
Viola 5.5 - 6.5
Zinnia 5.5 - 7.5
Raising pH Levels
Before modifying the soil pH, make sure to have a soil test to determine the current pH.
To raise the pH (or make more alkaline) by one point, supply roughly 30 pounds of garden limestone per 250 square feet. Incorporate into the soil or spread uniformly on top of the ground. Water well.
It may take a year or two for the soil pH to reflect the change.
*************************************************************
Lowering pH Levels
Before modifying the soil pH, make sure to have a soil test to determine the current pH.
To lower the pH (or make more acidic) by one pH point, supply roughly 3.25 pounds of garden or elemental sulfur per 250 square feet, depending on soil type. More sulfur would be needed for clay soils; less for sandy types. Incorporate the sulfur into the soil or spread on top of the ground. Water well.
It may take a year or two for the soil pH to reflect the change.
The use of pine needles and peat moss will also acidify the soil, though it is difficult to state accurate amounts needed.
