There are many easy to use soil testing kits that evaluate a sample of soil taken from the garden as either acid or alkaline. To be more accurate take a soil sample every 10 square meters and from the top 15 cm. Keep the soil samples from different places separately from one another in different bags. If required you can take samples from a deeper level in the soil, this is because the soil close to the surface is usually slightly more acidic than the soil from lower down in the ground.
Test you garden soil while is moist but not wet. Collect a sample of moist soil using a trowel or spade and place it in a plastic bag. Pour the soil sample out of the bag and onto a sheet of absorbent paper. This will help to draw moisture out of the soil if it is too wet. Crush the soil sample lightly with the back of your trowel, in order to break down any large lumps. Remove any large stones and discard them.
Use a test tube from a testing kit, add a measured amount of test chemical then a measured amount of soil from the sample then add distilled water up to the level indicated on the tube. Seal the tube and shake the contents for about a minute. Allow enough time for the sample to settle. Samples that have a high proportion of clay will usually take longer to settle and clear, because the very fine soil particles in clay are held in suspension for longer. The liquid from the tube will gradually change color, indicating the amount of lime in the soil sample. Compare the color against the chart. This test will give you a reasonably accurate reading of the lime content of your soil.
Store the chemicals from the soil testing kit in a cool, dark place, because they may deteriorate if exposed to sunlight for longer periods.