Seed Catalog Planning for the Garden

Plan before you open the seed catalog: check what seed you already have, list what you want to grow and how much space it needs, match each variety's days to maturity to your frost free season, favor disease resistant types for crops that struggled before, and then work out seed starting dates by counting back from your average last frost. Order early for popular varieties, buy a little extra for gaps, and write every date into one planner so nothing is started too early or too late.

A catalog is built to make everything look essential. A short plan turns it into a shopping list. It also prevents the classic mistakes: ordering three kinds of zucchini for a small bed, or starting tomatoes indoors so early that they are leggy and root bound by planting time.

Start with an inventory

Pull out last year's leftover packets and note the crop, variety, and packing year. Most seed stays good for a few years when stored cool and dry, but onions, parsnips, and some others fade fast. If you are unsure, run a quick paper towel germination test on ten seeds. See storing leftover garden seeds and testing if they still sprout for storage times and the test.

Then make a simple list: what grew well, what failed and why, and what your household actually ate. That list is the real starting point, not the catalog cover.

Match varieties to your season

Days to maturity is the key number. For crops usually set out as transplants, such as tomatoes and peppers, it is counted from transplanting. For direct sown crops, such as beans and squash, it is counted from sowing. Compare it with the number of days between your average last spring frost and first fall frost. Short season gardeners should favor varieties at the low end of the range.

Disease resistance codes save a lot of trouble. On tomatoes you may see letters such as V (verticillium wilt), F (fusarium wilt), N (nematodes), and TMV (tobacco mosaic virus). Cucumbers and squash may list PM for powdery mildew. If a disease hit your garden before, choose a variety that lists resistance to it.

Hybrid or open pollinated? Hybrids (often marked F1) tend to be uniform and vigorous, but seed saved from them will not come true. Open pollinated and heirloom varieties can be saved year to year.

Work out how much to order

Measure your beds and decide how many plants of each crop fit. Then add a margin of about 20 to 30 percent for poor germination, pests, and replanting gaps. Check the seed count on each packet; one packet of lettuce seed may cover several sowings, while a packet of hybrid tomato seed may hold only a couple dozen seeds. For crops you sow in succession, such as lettuce, radishes, and beans, plan two or three sowings a few weeks apart rather than one big planting.

Order popular varieties early in the season, since favorites often sell out, and order seed starting supplies at the same time so everything is on hand.

Build a seed starting calendar

Find your average last frost date, then count back. Typical indoor start times are:

• Onions and leeks: 10 to 12 weeks before the last frost.
• Peppers and eggplant: 8 to 10 weeks before.
• Tomatoes: 6 to 8 weeks before.
• Broccoli, cabbage, and other cool crops: about 4 to 6 weeks before they go out, which is often a few weeks before the last frost.
• Squash, cucumbers, and melons: 3 to 4 weeks before, or sow directly once the soil warms.

Write each start date in a planner or on the calendar, along with the transplant and direct sowing dates. For a broader month by month view, see the seasonal planting calendar.

Set up before the first sowing date

Check your trays, domes, heat mat, and lights a few weeks ahead. Seedlings need much more light than a windowsill gives in late winter, so plan on LED lights hung a few inches above the plants for about 14 to 16 hours a day. See LED grow lights for seed starting, seedling heat mats, and seed starting trays and humidity domes.

Safety notes

Use heat mats with a thermostat, keep cords and plugs away from water, and plug grow lights and mats into a grounded outlet or a power strip with overload protection. Never run a heat mat under a wet towel or on carpet. Some seed is coated with a fungicide, often dyed pink, blue, or green; wash your hands after sowing it and store it away from food.

Pet notes

Keep seed, seedlings, and supplies out of pet reach. Treated seed should never be eaten by people or animals. The ASPCA lists the green parts of tomato plants, and onions, garlic, leeks, and chives, as toxic to dogs and cats. Seedling trays on low shelves are tempting to cats, and slug baits and fertilizers used later in the garden can also be dangerous, so read every label. If a pet eats seed, seedlings, or garden products and seems unwell, call your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435. See what to do if a dog eats a plant.

Bottom line

Inventory your seed, list what you will really grow, choose varieties that fit your season and resist the diseases you have seen, order with a modest margin, and write a start date for every crop by counting back from the last frost. That one page plan makes the whole spring calmer.

Related reading

• Storing leftover garden seeds over winter
• Seed starting trays and humidity domes
• LED grow lights for seed starting indoors
• Seasonal planting calendar

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