Soil is way important when it comes to container gardening. Make sure you get POTTING SOIL. Anything else will not have the right drainage or nutrients to carry your veggies/fruits through the seasons.

Organic fertilizers, amended to the soil, will help, including Bone Meal (to help the plants flower, producing more fruit), Blood Meal (for plants that are heavy nitrogen feeders), and compost tea (this is just compost mixed with water). You can pick these up at Home Depot (Bone/Blood Meal) and Whole Foods (Silver Spring).

If you can, pick some Heirloom varieties. They preserve our plants’ genetic diversity and often taste better than regular varieties. Tomatoes, for example, come in an array of shapes and colors, including green, yellow, purple, pink, orange, and of course red. You can pick up a ton of Heirloom seeds at any Whole Foods. This is the brand name:
http://www.botanicalinterests.com/store/index_index.php

Certain vegetables can be sown now including peas, lettuce, spinach, broccoli, radishes, beets. You will need deeper containers for the root vegetables. Once these have grown it will be just the right time to put your warm weather vegetables out. Tomatoes, peppers, and herbs.

I find that Basil will grow easily. Mint will as well, but plant in its own pot as it will overtake anything else. Tomatoes/Peppers are pretty easy to grow. I’d recommend planting one tomato/pepper plant per pot. They will grow better and produce more fruit.

It’s true about the determinant or bush varieties of tomatoes. They will stay relatively small and manageable.

The best time to start your tomatoes/peppers would be within the next month or so. Start the seeds indoors, then transplant the seedlings into larger containers. Only put outside after April 15th or an unexpected freeze might kill them off.

Oh, and make sure you put out some flowers to get pollinators to help you out.

This book has been an inspiration to me for the past year: http://www.amazon.com/Garden-Anywhere-Alys-Fowler/dp/0811868753.

Root rot especially is the result of overwatering or poor drainage; if you let your plants sit in water, regardless of when you water, you’ll have problems. If you tend to overwater, maybe morning is better for you, since at least 30% of what you put on the soil will be evaporated within a couple of hours of summer sunlight. As for fungus, if you water the soil and not the leaves, it has no effect on fungal growth. Depending on your watering method, you may need to take that into account.

Good luck with your rooftop garden–you’ll enjoy both the experience and the harvest.

Linda Yang’s City Gardening Handbook has good info on weight and water considerations for urban gardeners. She’s a Manhattan-based gardener, so she’s very attuned on how not to flood your downstairs neighbor or create other garden-related problems.

and dripworks.com for automatic watering is totally worth it. Once you’ve set up the system (you need access to an outdoor faucet), it runs on a timer. The system is perfect for container plants.

And best of all are the “theme” garden suggestions sprinkled throughout the book—e.g., what vegetable/herb combinations to grow if you like Asian cuisine, or to cook Italian, etc.

A good book for city roof/balcony/terrace gardening is Linda Yang’s City Gardening Handbook. Ms. Yang is Manhattan-based–so her book talks a lot about container weights and watering and how not to cause damage to your balcony and/or the residents below.

And if you have access to an outdoor hose bib, look at http://www.dripworks.com for their drip watering kits which can be used with container gardens. The system is relatively easy to put together, operates on a timer, and is totally worth it. Happy gardening!

If I did this again I would definitely try to set up some automatic watering – you can get relatively inexpensive timers and hoses at Home Depot or Lowes and run small water lines to each pot. Seems like it would be a pain to set up the first time but I’m sure it would pay off – I want to try this for hanging baskets on our porch this summer.