Herb gardens are ideal subjects for hydroponic gardening. Not only do herbs grow fast, they're immediately useful.
Decide Which Herbs You Want to Grow
To save time, avoid different setups for different kinds of herbs. Start out with herbs that have similar requirements for feeding and Ph levels.
Start the Seeds
If you're going to grow your herbs from seeds, start them off before you put the hydroponic garden together.
Use Rock-Wool Grow Cubes
Grow cubes are designed for germinating seeds. They are available under various trade names. They are about an inch along each side and one face has a dimple pressed into it. Soak the cubes in water for 24 hours.
Plant the Seeds in Cubes
Put several seeds in each depression in each cube. Use three or more cubes for each herb you wish to grow. Place the cubes on a flat tray so that you know which herbs are where. Fill the tray with water to about a quarter of the way up the cubes.
Leave to Germinate
Put the trays where they will be safe and wait two weeks for the seeds to germinate and start growing. Check them regularly to ensure that they do not dry out.
Prepare the Garden
If you have a small old table you can use that to build your garden on.
The best thing to use for a herb garden is an opaque flat plastic container. It should be partitioned off so that each herb will grow independently of the others. This is probably best achieved by using a plant pot for each herb.
Make a hole near the bottom of the container in one corner and make a plug that will fit it. The plug should be water tight when inserted. Place the container on the table so that the drain hangs over the edge.
Put a layer of clay pellets about four inches deep in the bottom of the container. Firmly press a 6inch plant pot for each herb into the clay pellets. As you press more plant pots into the container the level of the pellets will rise. If they fill the plant pots, that is OK, although most unlikely. You will need a few inches of pellets at the bottom of each plant pot any way.
Put the Seedlings in the Plant Pots
After two weeks the seedlings will be big enough to move into the garden. Put the cubes for each herb into the same plant pot. A 6inch plant pot can probably hold six or seven cubes comfortably. Fill any gaps between the cubes with clay pellets.
Mix the Nutrient Solution
Mix up the nutrient solution and check the Ph level. Pour enough of the solution into the container to come up the sides of the plant pots to the base of the cubes.
Your herb garden is now ready to go into production. As the herbs grow they will bulk out and look very bushy. If you need to change the nutrient solution you can drain it using the drain hole you made in the container and simply add the fresh solution. Between draining the container and refilling it you should wait a couple of hours fro all the plant pots to drain.