In the last post I considered when you may prefer to obtain started plants for your garden and when you may prefer to start your plants from seeds. Let’s suppose you’ve decided to start some plants from seeds this year. The next question is whether to start your seeds in the garden spot where they are to live versus starting them in flats or pots in a more controlled environment for their first few weeks of life. In this post I’ll help you decide which of these work best for the plants you want to grow and the particulars of your situation.
One of the difficulties in deciding whether or not you want to start seeds early in a controlled environment is that garden publications offer such a wide range of advice on the matter. I discussed Steve Solomon’s approach to vegetable gardening in my January 26, 2012 post. Solomon thinks you should start almost every vegetable seed where it is to grow, except for tomatoes, eggplants, peppers, and possibly melons and squash. His reasoning is that by starting almost every seed in the garden, you can either eliminate the costs and work of raising seedlings in a special environment by buying these few as plants, or at least you can reduce the space, work, and cost involved to a minimum by only starting these few in a warm place since the seeds need a lot of warmth to get started and the plants need a long, warm season in which to grow and fruit. On the other hand, John Jeavons (January 19, 2012 post) thinks you should start almost every vegetable seed in a controlled environment, with the only exception being radishes. His argument is that you can use the bed space more intensively by growing plants to transplanting size in flats (something else can be growing in the garden bed in the meantime); the plants you put out are pretty certain to be healthy and to grow well; you can space plants evenly more easily than you can seeds, and the plants will produce a better growing environment in the bed sooner than tiny seedlings will; transplanting stimulates growth; and seedlings in a flat require much less water per unit area than seedlings in a bed, since seedlings in a flat are growing very close and can produce a good growing environment in the small area of a flat. Both positions seem reasonable; in fact, they describe all the pros and cons of sowing seeds directly versus starting them early better than I could have. How can you, as a beginning gardener, decide between these approaches? What other factors should be considered that neither man addresses?
It’s important to realize that both men are gardening in very different climatic conditions than we are in the St. Louis metro area, and their climates influence their recommendations. Each kind of vegetable (and for that matter, herb, flower, and any other kind of plant) has its own range of climate conditions required for germinating and growing its seeds and for growing the resulting plant. You, as a gardener, need to meet the seeds’ and plants’ requirements as best you can within the climatic conditions under which you live. If you are growing in an environment like Jeavons’ with a lot of rain from late fall through early spring and very little rain the rest of the year, with a mild winter compared to St. Louis (the lows in Willits, CA don’t go under 20F) and with a wide daily temperature range during the dry season, you’ll do better by starting as many seeds as possible indoors or within a cold frame, then transplanting larger plants better able to handle wide temperature swings and dry soil in the garden. In contrast, Solomon used to garden in the Pacific Northwest and now gardens in Tasmania. In both places a cool maritime climate is favorable to sprouting and growing most kinds of seeds sown directly in the garden, and the only reason to start plants indoors is to give heat-loving plants the biggest head start possible so he can get something out of them. Here in St. Louis, where cold frames don’t get warm enough to start anything till March and then only cool-weather crops, where we have a short spring with wide temperature swings from day to day transitioning to a long, hot summer and then to a short fall with wide temperature swings from day to day, the question of what seeds to sow directly in the garden and what seeds to start inside is more complex. In many cases we can do either and be successful; then it comes down to how much space and time we have to devote to starting plants early. I’ll help you think through this question in the rest of this post.
The easiest question to answer is which vegetable seeds really need to be started early in a controlled environment in St. Louis and other areas with similar climates to ours. Peppers, tomatoes, and eggplants are the plants that most benefit from an early start indoors, for the same reasons that Solomon starts them indoors: the seeds need a very warm start and the plants need to grow for many weeks before producing the parts we harvest. It doesn’t get warm enough here to start these seeds in the garden till May (tomatoes) or June (peppers and eggplants); only if we used the shortest-season varieties available would we be likely to get a harvest before our first fall frost kills the plants. If you can’t or don’t want to start these seeds early, in February or March, and you want to grow anything other than the shortest-season varieties, then obtain them as plants.
At the other end of the scale, everyone starts radishes directly in the garden because they are taprooted and thus difficult to transplant, and because they grow to harvest size very quickly, within a month or two. Almost everyone except for Jeavons direct-sows seeds of turnips, carrots, peas, beans, and corn where they are to grow because these plants grow well from direct-seeding but aren’t well suited to life in a flat, either because they are difficult to transplant due to taproots or because they can only remain in a flat for a few days before they become too large to transplant successfully. Following Jeavons’ advice, I have sown carrots, turnips, and corn in flats and transplanted them to the garden. It worked, but it took more time than sowing directly to the garden, and in the case of the carrots, I broke the taproot during planting and got poorly-shaped roots as a result. I’ve also had some difficulty germinating carrots in a flat, perhaps because the soil dried out during the time the seeds were germinating. I now sow all of these seeds directly to the garden and suggest you do the same unless you really enjoy starting seeds in flats and have room enough to try these.
Our springs tend to be short, with wide temperature swings from day to day as cold and warm fronts battle it out for dominance. Our soil is often frozen into early and sometimes mid-March; yet by June 1 our average high is 81F, our average low is 62F, and the lowest temperatures ever recorded in June are in the mid to upper 40s, with record lows above 50F by the last week or two. By the end of June the average high is 89F and the average low is 70F, not conditions under which crops that like cool weather thrive, or even survive. (All climate info is from the St. Louis National Weather Service office.) Vegetables that like cool growing conditions and need more than two months to grow to harvest size are good candidates to start early in a controlled environment in our area, if you can make a space suitable to their needs and are willing to tend them. Missouri Extension publication G6570, Starting Plants Indoors From Seeds, has a good list of vegetables to start indoors. They include broccoli, cabbage, kale, collards, and head lettuce. If you search seed catalogs for short-season varieties of these and you sow them by the end of March (all but lettuce; sow lettuce seeds in early to mid April), you could sow seeds directly in the garden with good success; I recommend this if you don’t think you have the space to start seedlings inside or you can’t meet their needs. I start all of these, including all lettuces and also bok choy, inside in early February to early March and transplant several-week old plants to the garden. Weather conditions can turn cold in spring, delaying germination and perhaps rotting direct-sown seeds before they germinate. Seedlings grow slowly in cold soil. Lows in the teens in late March or low twenties in early April can kill seedlings. I find it preferable to transplant strong, healthy plants into the garden around mid April, once it seems likely that temperatures won’t go much below freezing and the soil begins to get warm enough to hasten growth. Strong plants dig in and grow better and are more likely to survive the occasional hot spell to produce a good harvest from late May through June and into early July, before the weather gets too hot.
For plants like beets and kohlrabi, which mature within about two months or so from direct-sowing to the garden but can be grown in a flat and transplanted, you have the most options. Garden centers offer seedlings for sale, if you prefer to start with plants someone else grew. You can also sow these directly into the garden in April or start them in flats indoors in March and transplant them into the garden around mid April.
You also have options with melons, squashes, zucchini, cucumbers, and okra. Their seeds need a warm start and the plants need warm weather to grow, but they germinate and grow fast enough that they can be sown directly to the garden in May or June. You’ll find seedlings of melons, squashes (and pumpkins, another name for some kinds of squash), zucchini, and cucumbers readily available for purchase, but these are so easy to direct-sow in the garden or to start indoors in small pots and transplant that they make good seeds to start with when you are first learning to grow plants from seeds. I’m not a big fan of okra so I haven’t noticed if you can buy okra plants at garden centers, but I did grow it from seed one year, planting the seeds directly in the garden in early June, and they produced a high yield. Missouri Extension says you can start okra seeds early in small pots in late April, transplanting about a month later, or direct-seed into the garden in May.
For other plants, you use a similar process of evaluating the conditions the seeds need to germinate and grow and the growing conditions and time needed to grow plants to harvest or flowering stages. Most gardening books, including the books I’ve discussed in earlier posts, include this information for commonly grown vegetables, herbs, and flowers. You should be able to find it on the Web as well. Compare these requirements to the climate in your location to decide whether to sow seeds directly to the garden or whether to start them early inside, if you can meet their needs and have enough space. Spring herbs like dill and parsley grow quickly and can be either direct-sown or started inside in the St. Louis area. I generally start them inside, because I have plenty of space and enjoy caring for seedlings; if you don’t, direct-sowing at the proper time works fine. Basil, on the other hand, can’t tolerate frost and needs warm conditions to germinate seeds and a long time to grow to harvest size, so I and most other people who start it from seeds start it early indoors. If you don’t want to start it from seeds, obtain started plants, which should be easy to find.
If you are in the U.S., you can find climate information for your location, including average and record highs and lows, from the nearest office of the National Weather Service. Your state Extension service should have general information on how to grow vegetables and other commonly grown plants in your state, including publications for downloading and printing. If you live in a mountainous area, your climate is altitude-specific; you may need get information from local resources for gardeners in order to know what works best for you. Folks in other parts of the world should consult with the appropriate organizations in their area. The best source of information may be a knowledgeable gardening neighbor!
In the next post, which I intend to get up by March 1, I’ll offer some guidance on how to start and where to grow the seeds you need or want to start in a controlled area, whether in the house, on a porch, or in a cold frame. There’s still time to start these seeds in the St. Louis area, so get the seeds you want to start while I’m writing the next post!