"It's so hot, you have to be careful to get your seeds to germinate."
Smith Fiola suggests shading the area where cool-weather crops have been planted until the plants begin to mature.
Koeneke said planning is also necessary to create a successful crop rotation. A successful crop rotation takes into account plants that benefit each other as well as their nutrient needs. For example, Koeneke said he is planning to plant his carrots and radishes together because the radishes will benefit the carrots.
"Radishes grow faster and break up the soil, making it easier for the carrots to grow," he said.
He suggests following heavy feeder warm-weather vegetables with light feeder cool-weather vegetables. He said heavy feeders include tomatoes, sweet peppers and broccoli.
"(Heavy feeders) require more nutrients," he said. "Spinach and lettuce don't draw as many nutrients out of the ground."
For a healthy garden, Koeneke said it is also important to put nutrients back into the soil. A nitrogen-fixing plant, such as peas, takes nitrogen from the air and puts it into the soil.
Know your plants
"There are certain pairs (of plants) that either attract beneficial bugs or repel unwanted bugs," he said.
The combination of basil and tomatoes is one such example. There are also practical culinary considerations when planning a garden.
"You want to be sure you start your cilantro, because your tomatoes are going to be ripe, and you're going to want to make salsa," Smith Fiola said.
In a vegetable garden, late summer is the time to be planting and preparing for cool-weather crops, but in a perennial flower garden it is the time to prepare for winter, and even next years growing season.
"I don't do a whole lot of planting in the fall," Burns said. She focuses on preparing her flower beds for the next years growing season, she said.
"Fall is a great time to start a new bed, either vegetable or a flower bed, and get it ready to go for the next spring," she said. "(The) work of building and digging goes much faster in cooler weather."
The care of perennials varies, so it is best to consult a reputable resource to learn the recommended care of a specific plant.
Smith Fiola suggests gardeners call the University of Maryland Home and Garden Information Center if they have questions about plant care.
"There are so many different plants, and they each have their own little rules," she said.