By Steve Reiners, Professor and Chair, Horticulture Section, School of Integrative Plant Science, Cornell University, Cornell AgriTech. This is part of a series of columns that he wrote about vegetable gardening during the pandemic. 
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March 19, 2021

Spring is almost here and I’m sure gardeners can’t wait to get outside.  Even though it’s still March and your soil is probably not quite ready to work, now is the perfect time to plan your vegetable garden.   

I love to put a plan down on paper so I’ll be ready to go once planting season starts.  For peas and spinach, that could be as soon as next week.  It’s much better to have a well-thought-out plan ready to go than to make decisions on the fly the first nice Saturday in April.

First thing to include on your list: What do you want to grow?  Ask yourself these questions: 

• What do you and your family like to eat? 
• What have you grown successfully in the past? 
• What failures have you had?
• Did you have too much of any vegetable last season? 
• Is there anything new you would like to try?

Now that you have a list, consider planting times.  We have heat-loving vegetables that require warm temperatures.  Plant these after the last spring frost and the soil has had a chance to warm up, around May 20 in our region. 

We have cool-season vegetables that stand up to a frost but may wilt and die in a hot summer.  These can go out early in the spring, and many can be replanted again in the fall.

We also have some that can handle cool and warm temperatures.  Use Table 1 below to see which crops on your list belong in which group.

Now, where to plant them in the garden?  Try to remember where things were planted last year or check last year’s plan.  Avoid planting the same type of vegetable in the same bed.  Some pests and diseases can overwinter in soil from last year's crop and attack this year’s crop. 

Farmers do this all the time. It’s called crop rotation.  They try to wait at least three years between similar crops.  In a small garden, it’s less important. But it's still helpful.  And think broadly when planning your rotation and try to keep vegetable family members from following each other:

• Aster –  artichoke, endive, escarole, lettuce, radicchio
• Brassica - bok choi, broccoli, Brussels sprouts, cabbage, cauliflower, kale, mustard greens, parsnips, radishes, rutabagas, turnips
• Cucurbit - cucumbers, gourds, melons, pumpkins, squash
• Goosefoot  – beets,  Swiss chard, spinach
• Grass  - sweet corn
• Legumes – beans, peas
• Mint – basil, lavender, mint, oregano, rosemary, sage, sweet marjoram, thyme
• Morning glory – sweet potato
• Nightshade - potatoes (white), tomatoes, peppers, eggplant
• Onion- chives, garlic, leeks, onions (bulb and green)
• Parsley – carrot, celery, fennel, parsley

Don’t forget about plant height and shading.  Keep tall growing plants on the north side to avoid shading smaller plants.  Aim to have fruiting vegetables like tomatoes, peppers and squash in the sunniest part of the garden. Leafy greens and spinach can still perform well if shaded a bit by nearby crops.

Maximize space with succession planting – growing two or more crops in the same space. For example, an early crop of peas is finished by the 4th of July.  Plant a heat-loving crop like beans or zucchini right after final pea harvest.  Follow these with a fall crop of spinach or overwintering garlic. Three crops in the same location!

Planning lets you to estimate how many seeds or plants you will need.  And if you are buying seeds, don’t wait any longer as seed packets are flying off shelves this spring.  Table 2 below provides yield estimates for your garden, based on typical plant spacings.

We’ve also archived last year’s series of columns that provides additional timely information through the growing season:

And if you have any gardening questions, please send them to me at sr43 [at] cornell.edu (sr43[at]cornell[dot]edu). I will try to answer them in future columns.