In fact plants acidic fertilizer is also important as that of organic fertilizers for plants (azaleas,roses,rhododendrons, blueberry, hibiscus and other acid-loving plants) needs acidic fertilizers.For instance,eggshells are almost 100% calcium carbonate, one of the main ingredients in agricultural lime; vinegar has acetic acid; & coffee not only lowers your soil pH ,it also enriches it with nitrogen,magnesium and potassium.
too much use of fertilizer can make soil too acidic so thee fertilizers should be used in a limit.

EPSOM SALT FERTILIZER
COFFEE GROUND FERTILIZER
EGG SHELL FERTILIZER
VINEGAR FERTILIZER
FISH TANK FERTILIZER

are some of the accidic fertilizers wich can be made in home with less cost for plants.

Step 1: Epsom Salt Fertilizer

Epsom salt fertilizer:use in place vegetable plants,rose plant, peppers,houseplants

ingredients:
1 table spoon Epsom salt
1 gallon of water

combine the Epsom salt and water and use this solution to water your plants.repeat once a month. Epsom salt is made up of magnesium and sulphate-both vital plant nutrients.

Step 2: Coffee Ground Fertilizer

coffee ground fertilizer:used for rose plant.

ingredients:
used coffee grounds
newspaper

spread news paper.then spread used coffee grounds out on the paper and allow them to dry completely in sunlight for about 2-3 days.sprinkle the coffee ground around the base of your rose plant.

Step 3: Eggshell Fertilizer

Egg shell fertilizer:used for all kind of plants

ingredients:
Egg shells
Blender

save your egg shells and allow them to dry.place the dried shell in the blender and pulse until they are turned to fine powder.Sprinkle in your garden.Eggshells are made up almost calcium carbonate.

Step 4: Vinegar Fertilizer

vinegar fertilizer:used for houseplants and vegetable plants

ingredients:
1 table spoon white vinegar
1 gallon of water

combine the white vinegar and water. use the solution to water your plants.repeat every three months.the acetic acid in vinegar works to increase the acidity of the soil.

Step 5: Fish Tank Fertilizer

Fish tank fertilizer:used for any plants

save the dirty water from fish tank and use it for watering plants.Used fish tank water is full of nitrogen and other ingredients and plants need thrive.