This is the seventh in a twelve part series for new gardeners. If you have never planted vegetables before but always wanted to, this is the series for you. Robin, who writes the blog Vegetable Matter, and I will post on the first of every month. Robin lives in Houston and I live in Boston. We will be posting about what to do in the garden that month and giving advice. So if you have always wanted that vegetable garden, but didn’t know where to start, you have no excuse. Get growing!
Growing Fall Transplants And Fighting Diseases
Fall Crops Now?
In New England in June the summer garden of tomatoes, peppers, beans and squash is well on its way and the spring garden of peas, broccoli, Asian greens, and cabbage is being harvested. The garden is fully planted up and growing well - hopefully. It is hard to imagine the fall right now as the weather is just heating up, but June is the time to start your fall transplants. It is often hard to find fall crops in the garden centers, so it is often best to grow your own.
These transplants will be ready to put in the garden in mid to late July. The spring crops will all have been harvested by then so there will be space for the transplants. Some people direct seed these crops in the garden, but I find for many that there isn't time for both a spring and a fall crop if I don't start transplants.
So which crops should you seed now? Any fall crops that take 60 days or more to mature, except carrots which need to be direct seeded in July. These include broccoli, cabbage, lettuce, and any of the longer maturing of the Asian greens like Chinese Cabbage. If you had trouble with any of the brassicas (all in the list but lettuce) then you will have an easier time growing them in the fall. The weather fluctuations and growing heat of spring often causes these to bolt in the spring, but in the fall the cooling temperatures are more to their liking.
Planting one crop when another crop comes out is called succession planting. It keeps a small garden more productive. I also succession plant some of the more heat resistant Asian greens, like green stemmed bok choy, mizuna, and Komatsuna, but for these I do it more often. I will grow a new batch of seedlings every two to three weeks and as a few plants get pulled, I have the next one waiting to take its place. You don't need to grow transplants for these. You can direct seed as soon as your plants comes out, but if you have a small space, you will get larger harvests by growing transplants or having a small section of the bed devoted to seedlings for transplanting.
When I do successions I typically replace lettuce with lettuce and bok choy with bok choy, but you can't do this from year to year. There are many plant diseases that will build up in the soil over time.
How to Control Plant Disease in the Garden
The best way to control disease in the garden is by crop rotation. Crop rotation is just moving which plants grow in which section of the garden every year. Each family of plants has their own set of diseases and moving them every year will keep diseased soil from infecting your plants. A few diseases will cross family lines but not may. So to set up a rotation schedule in your garden you need to know what plants are in what families.
- Amaryllidacaea Family often called the Alliums: leeks, onions, chives, garlic
- Brassicaceae Family often called Brassicas or cole crops: broccoli, cauliflower, mustards, cabbage, rutabaga, kale, collards, cress, radish, rocket, turnips, Asian greens
- Chenopodiaceae Family: beets, Swiss chard, spinach
- Compositae Family: artichokes, sunflowers, lettuce
- Cucurbitaceae Family often called cucurbits: squash, pumpkins, zucchini, gourds, melons
- Leguminosea Family often called legumes: beans, peas, peanuts
- Solanaceae Family often called nightshade crops or solanums: peppers, tomatoes, potatoes, tomatillos, eggplants
- Umbelliferae Family: dill, carrots, coriander or cilantro, fennel, parsnips, parsley, celery
More experienced gardeners might noticed that I left at least one major crop out. I don't have corn on the list because its family has very few edibles (corn and sorghum), so they are in their own rotation.
Some plants have disease that don't persist in the soil very long. Some have diseases that can last a long time in the soil. The worse is probably the brassicas. The have a disease (clubfoot) that can persist in the soil for years. Usually a rotation of 6-8 years is recommended. Which means you want to plant a different crop there for 5-7 years before the soil sees a brassica again. This is not always easy to do. The second worst is probably the solanums. This is not because they need such a long rotation, but because they have so many soil born diseases. There is never a year that goes by when my tomatoes aren't infected with at least one disease. They need to be rotated on at least a three year schedule, but four is better. I use a three year schedule because I love my solanums so much. So a third of the garden is always devoted to them. Each year it is a different third.
Rotation also helps the soil for another reason. Some plants are light feeders and some are heavy feeders. For instance, beans can actually set nitrogen on their roots. The legumes are the only plants that can do this. So if they follow something that is a heavy feeder (like lettuce and brassicas) they can help to balance out the nutrients in the soil.
But back to diseases. Even rotating your crops will not prevent all diseases. If it is a wet year in New England you will have many diseases anyway. Some are just endemic to the area. You will have powdery mildew on your zucchini in the late summer to fall. It is just a given. There are a few ways to help keep diseases from running rampant. First make sure you don't crowd your plants too close together. For instance if your tomatoes are a solid mass of leaves, it would behoove you to prune some of the foliage out to keep the air flowing.
Second don't work in the garden when it is wet. Some plants, like beans, have a greater disease transmission when you touch the wet plants. It is best to stay out of the bean patch when it is damp. Wait to pick until the leaves dry off.
Third, when you see a diseased leaf in the garden you can pick it off and destroy it. Make sure if you use tools on infected plants to wash them off afterward. Most people will recommend that you use a 10% bleach solution to sterilize them. If you don't, you will just be spreading the disease around the garden.
Fourth you can spray. I don't like to spray with toxic materials in the garden. I stick with safer things. For powdery mildew you can spray a 10% solution of milk diluted with water. Since I don't usually have milk in the house, I spray my plants with a mixture of worm compost tea and aspirin (3/4 of a tablet per gallon of water - aspirin has been shown to switch on a tomato's own disease fighting mechanisms). If it is a very wet year, I alternate the above spray with Seranade. Seranade's active ingredient is a bacteria that destroys spores.
In the Northeast you will never have a year without diseases in your garden, but with good gardening practices you can at least keep them to a manageable level. My beans might always get rust every year, but the beans are still very productive. The tomatoes will get Septoria Leaf Spot no matter what I do, but I will still get many tomatoes off of my plants.
Last year was a particularly bad year for tomatoes as Late Blight was rampant in the Northeast, but I was vigilant. Every day I was out in the garden checking the plants. I picked off any diseased leaf or stem and disposed of it properly (for Late Blight this means bagging in a black plastic bag, sealing it and setting it in the sun for a few days to kill off the spores). I still had a good harvest. My potatoes were also infected so when I harvested them I made sure to get every last one of them out of the soil. Late blight can't over winter here except on live plant material. For us this means potatoes left in the soil. I even double dug that section of the garden to make sure no potato was left. If one potato overwintered and came up in the spring it would mean that my garden would be reinfected. Not everyone last year was as good as I was. There are already reports of Late Blight overwintering in potatoes in Pennsylvania and Maryland. An outbreak is already starting. So this year we may have issues again. The Massachusetts extension service has a page up to help you identify and tell you want to do.
Other post in the seriesDetermining your growing zone and planting peas (Vegetable Matter - December)
Planning a Garden (Daphne's Dandelions - December)
Growing Lettuce (Vegetable Matter - January)
Starting transplants indoors (Daphne's Dandelions - January)
Growing tomatoes (Vegetable Matter - February)
Compost (Daphne's Dandelions - February)
Snap Beans (Vegetable Matter - March)
Peas and Spinach (Daphne's Dandelions - March)
Eggplant (Vegetable Matter - April)
Brassicas (Broccoli, Cabbage, Asian vegetables) (Daphne's Dandelions - April)
Edamame (Vegetable Matter - May)
Tomatoes (Daphne's Dandelions - May)