On average, listings lease in the $10's per square foot per year. The Lemon Grove submarket is going through a a boost in rates. In the last 3 months, the median rate rose $14 per sqft per year. That's a Inf% increase in rent.
Compared to the rest of the San Diego market, the Lemon Grove submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 5 listings have come on the market, which means new listings are probably leasing quickly. You'll want to be prepared to tour spaces as quick as possible. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 780 sqft. Most properties in this market are close to 2 floors. Most buildings in this market were built in 1985 and are Class Class C.