Moisture is another requisite, it needs persistent daily watering, but avoid allowing water to puddle up to avoid fungal issues both above and below the soil surface. Never let the roots dry out, a little mulch goes a long way in moisture retention.
Full Sun is best, even partial shade is not advisable, although the plant would probably survive it wouldn't thrive.
Optimal Spacing - 2 Feet
During its active growth season it should be fertilized every other week. A mild mixture of seaweed extract, fish emulsion or blood meal will suffice.
Pests are not a major concern with Lemon grass. It actually repels many common garden pests and works well in companion planting scenarios for this reason. Lemon Grass is related to Citronella grass and both contain citronella, frequently used as a mosquito repellent. Lemongrass is also proven effective against mites and ticks as well . Also See - Herbal Pest Control
Harvest when the plants are about a foot tall, the stem bases should be about a half inch thick. Cut stalks below the base but just above the ground level. You can also hand pull up the entire plant to be sure to get the onion like base. Its bulbous base stem is the best part, it is packed with citrusy lemon flavor. Leaves can be harvested periodically as well.
In order to use lemongrass in any recipes that call for it remove the hard outer layers and use only the softer layers inside.
Lemon Verbena Lemon Balm Herb Gardens Tea Gardens