Tips to Prevent Overwintering Late Blight

Late blight (Phytophthora infestans) occurs commonly each year in many places around the United States and the world.

There are steps we, as home gardeners, market farmers and commercial growers alike, can take in order to reduce late blight inoculum surviving the winter.

The following tips for fall will help prevent the spread of late blight (Phytophthora infestans). They are different from summer management techniques:

» If possible, start with new seed potatoes in the spring that have been certified disease free.

» Cull any potatoes that are suspect before putting them into storage – potato tubers with late blight will have a dry, reddish brown rot in the flesh.

» Turn soil in garden or fields so that crop residues can readily decompose – late blight needs live tissue to survive. This includes tomato crop residue as well. As long as tissues decompose or die (no living plant tissue), then the late blight on that plant tissue will be killed as well.

» Cull potatoes in storage throughout fall and winter months that are suspect.

» Try to dig up all possible tubers – cull volunteer plants that emerge in the spring.

» Cull piles should be thin enough to freeze solid over the winter.

» Cull piles can also be managed so that they heat up significantly – this is achieved by adding the proper mix of brown and green ingredients to your compost pile and turning. A compost thermometer might be helpful.

» In the northeast US only one type of late blight is found so all measures outlined above will help prevent late blight from overwintering. In some parts of the United States and the world two different types of late blight can be found in the same location thus allowing the pathogen to ‘mate’ and produce oospores, capable of
surviving temperature extremes – in this case crop rotation is very important in reducing oospore inoculum on possible plant hosts. Crop rotation is important in all growing areas, no matter the size of your garden/field.

A walk around the farm this week and I’ve got a two page list of things that need to be done before the ground freezes. There’s all those tomato trellises to take down; the top wire to be rolled up, the tomato vines need to be cut off and piled up to be disposed of, thousands of wood and steel stakes need to be pulled, sorted and stacked, and the plastic and drip tape needs pulling and disposing of. Once that’s done, we chisel plow the field and that one’s ready for next spring.

We’re finished picking tomatoes, at least for seed. We picked two last week – one small cherry that took the entire farm crew two days just to pick it and one heirloom that took only a couple of hours. We picked the last tomato Monday this week and now can focus on other crops that need to come in. We’ve got a cucumber to harvest this week and we’ll bring our squash and pumpkins in from the field too. We’ll start processing the cucurbits week after next when I get back from my annual fall vacation. Yes, I said “vacation” in the middle of October!

Last year I took three days off in October to join some friends at their hunting camp “Downeast”. Their camp is located at the end of a huge field of blueberries owned by Jasper Wyman. Twenty minutes into our bird hunt I slipped and threw my back out. Two days of resting at camp and I’m headed home on the third day. This year I’m headed due north; to stay at another friends camp for up to a week or until I get to feeling guilty about leaving all this work for the farm crew. Ha.

All that plastic we put down this spring is about ready to be pulled now; miles of it, around 18 miles to be more precise. Its unfortunate there’s no way to recycle all that poly; it’s just too dirty to do anything with. There are some promising biodegradable plastics out there but nothing really good that approved for organic growers. And the ones that conventional growers can use are priced pretty high. So, what do you do?

We do however recycle lots of nutrients at the farm. Because we don’t harvest a lot of what we grow the nutrients are recycled back into the soil to feed subsequent generations of plants. Hundreds of pumpkins melting in the fields may seem like a waste but in the overall picture it’s just recycling at its best. Much food is donated to local food pantries and employees get their fair share as well but I’d just as soon see some of these crops go right back into the soil. I used to shudder at the thought of plowing under a field or part of a field of perennial flowers but now I realize it’s just more organic matter and nutrient recycling we’re doing here.

Until the 21st, enjoy the fall, Brian

Running irrigation water to prevent frost damage has its drawbacks. If anything is going to go wrong it will be at 2:30 in the morning; not the day you set it up. We set up the system on Thursday, blew out the lines and pressure tested it and everything was fine. Saturday morning sometime between when I left and when I returned is when something went wrong. The pump is now in the shop, completely disassembled, while we’re waiting on information from the dealer. There’s no frost in sight, at least for a week, so we should be all set; of course that’s subject to change according to the local weathermen.

The galinsoga is dead, and I mean dead. It has absolutely no frost tolerance so, except for where we irrigated, it’s dead in every field I toured this week. Speaking of touring the fields, I did my usual field visits this week, Monday, and all the fields except Jack’s had been frosted. Jack’s escaped frost by being near the pond and being on a hill. All the squash and pumpkins got heavily frosted so they’re easy to see and will be easier to pick than if the leaves were still up. For long term storage you’d not want them to get frosted, but for seed it’s fine.

We’re still picking tomatoes; we’ve got two or three to pick this week and we’ll be done with the tomatoes for seed production. We’ve got lots of seed from the tomato breeding workshop to seed out so that will keep us busy for quite some time. We’ve got squash and pumpkins to harvest for seed as well as a cucumber. We’ve got peppers, squash and pumpkins to harvest from the breeding workshops and we’ve got the usual plastic removal, miles of tomato trellises to take down, chisel plowing and equipment cleaning and repair to do in the next couple of months. Guess we’ll keep busy.

Even though we don’t harvest crops like a regular vegetable farm, we are more than busy saving seed for use in future years. I think growing for seed is much more interesting than growing for fruit. If you grow a tomato plant to eat, once you’re done eating them, well you’re done. But seed on the other hand is more of a whole circle type of experience. You grow the plants, harvest some for eating and harvest some more for seed. Next year you plant the seed that you grew and start the process all over again. This is where a lot of heirlooms come from; people saving their own seeds from their own climates with their own likenesses for generations.

Saving seeds from cucumbers, melons, tomatoes and peppers is relatively easy. Once you become proficient at saving these, moving on to biennials brings more of a challenge. Carrots, beets, turnips, Swiss chard and parsnips to name a few, all need two growing seasons to complete their life cycle. Each of these needs to be stored through the winter, replanted in the spring and harvested in mid-summer.

Until next week, savor the harvest. Brian

F is for Frost; among other things but I’m thinking about frost. We had a close call last weekend; Saturday night to be specific. All week and all weekend I tracked the weather trying to get an exact temperature for Saturday night. I got temps between 35 and 42 according to whom I listened to. There are several sources I rely on, most of the time being the National Weather Service out of Gray, Maine. Intellicast (www.intellicast.com) and the Weather Underground (www.wunderground.com) are also good bets.

There are a few guidelines I use when determining whether or not they’ll be a frost or not. If the wind is blowing we won’t have a frost, if the temperature at ten o’clock the night before is 40 degrees or above, we won’t have a frost, or if it’s raining we won’t have a frost (of course not). The temperature at the house was 47 at ten o’clock Saturday night but had dropped fast to 34 degrees at 3:00 AM. And every hour when I checked the temp it was 34 degrees until it warmed up as the sun came up.

Monday morning I went for my usual tour of our fields and crops. Of the five different locations I checked, there was frost damage at only one. That field always gets frosted early; this year is no exception. We have winter squash at that field; it’s a lot easier to see the fruits now. Not enough damage to be concerned about; the fruits will continue to ripen as the vines will continue to feed them. The fruits will be fine as long as they don’t get a killing frost or freeze. Only after a killing frost will damage be more severe; a hard frost and the fruits won’t keep.

There are some good things about a hard frost; for example a hard frost will kill Galinsoga. Galinsoga is extremely susceptible to cold temperatures so any temp below 32 will kill it; doesn’t hurt my feelings. Other indicators of frost temps are basil, squash and pumpkins, millet, and Sudan grass; all easily damaged by cold temps.

Preventing frost damage at the farm is reserved for the peppers and tomatoes. We use overhead irrigation to prevent frost damage. I’m sure there’s a scientific explanation for how it works but basically the energy released from the water freezing on the plants keeps the plants at 32 degrees and no colder. This works down to around 28 degrees or so. The biggest problem with this form of frost control, besides the labor to set it up, is putting a tremendous amount of water on the field. Several nights of frosts will saturate the field with water making field work all but impossible.

The leaves are turning quickly. It’s easy to miss them as farming is usually confined to working beneath your feet so gawking around and looking off into space isn’t something we do a lot of. I noticed the red maples in their full fall glory this morning whilst taking my dogs for their morning jaunt. I believe the correct name is red maple because their leaves turn red in the fall. The local name is white maple because their wood is white. Either way they are the first leaves to turn in the late summer. Stressful conditions, like drought and beaver damage, will make their leaves turn red pre-fall; sometimes in the summer even.

The fall migration continues; the swallows and hummingbirds are gone, the geese are flocking up; feeding heavily before their long trip. I haven’t seen a lot of ducks this year; they’ll probably be later in the season. Went to Jackman and Greenville two weeks ago Saturday and didn’t see any partridge but did see some turkeys and a flock of guinea hens. Yes, guinea hens. Beside route 201 on the way to Jackman, just out and about, not seeming to know where they were going or where they’d been or where they belonged.

I assume all the rain we had this summer took its toll on the partridge population. Rainy, cool weather will take a heavy toll on the chicks. Speaking of hatching issues, our setting hens did poorly this year, with only two chicks that survived until adult hood; well, at least they’re both hens. Fortunately the incubator I ordered worked out well and we’ve plenty of replacement laying hens and some roosters for soup to eat this winter. A couple of years ago Peggy wanted to make a chicken soup and was going to use breast meat. A 20 minute trip to the henhouse gave her lots of fresh chicken to make her soup. She hasn’t mentioned making soup since; works for me.

Until next week, enjoy the fall, Brian

Common name: Whitefly (Silverleaf, Greenhouse, Bandedwinged, Sweetpotato, and others)

Latin Name (in order of common names listed parenthetically above): Bemisia argentifolii Bellows & Perring, Trialeurodes vaporariorum (Westwood), Trialeurodes abutilonea (Haldeman), Bemisia tabaci (Gennadius)

Life Cycle: Overwinter in weeds and ornamental plants, multiple generations per year, adults lay eggs (10’s to 100’s at a time), four instars from egg to adult, first stage is crawler, remaining are stationary until adult stage, Greenhouse whitefly has circular pupae with flat top, resembling tuna fish can with filaments emerging from top of can, while Silverleaf and Sweetpotato pupae are convex and no flat top , use pupal or instar stages to ID species/strain , most species/strains of whitefly excrete and lay eggs in waxy residues left on leaf surfaces, entire generation can take as little as 16 days

Plants affected/Damage seen: Hundreds of different types to include but not limited to: Solanaceae, Cruciferae, Malvaceae, Luguminosae families; whitefly in the greenhouse will attack more plant species than if outside, stipule scarring seen, deformed leaf/blossom growth

Insect Habit: Piercing sucking mouthparts can transmit viruses readily, especially in a closed greenhouse, crawler stage moves to vein, inserts mouthparts and begins feeding, then stays immobile for the next three molts until emerging as adult

Control: Use yellow sticky cards and a hand lens to identify species or strain and to monitor populations, destroy heavily infested plants immediately, prune out heavily infested leaves or plant parts, dispose of vegetable plants as soon as harvest is over, inspect new transplants for infestations before planting in your garden, hoop house or greenhouse, encourage natural enemies (green lacewing, ladybeetle, big eyed bug, minute pirate bug, damsel bug), if infestation is severe, insecticides and introduced biological controls might be needed (PLEASE CHECK WITH YOUR LOCAL HORTICULTURAL EXTENSION AGENT REGARDING EFFECTIVE BIOLOGICAL AND CHEMICAL CONTROLS FOR YOUR AREA), resistance to insecticides has been found in whitefly populations due to multiple generations per growing season

References:
http://www.entnemdept.ufl.edu/fasulo/whiteflies/wfly0082.htm
http://www.uckac.edu/whitefly/faqs_about_whiteflies.htm
http://www.uckac.edu/whitefly/faqs_about_whiteflies.htm

There’s still time to plant

In frost-free climates, you can plant cool-weather crops outside to harvest throughout the fall and winter. These include arugula, beets, broccoli, cabbage, carrots, cauliflower, celery, collards, kale, lettuce, onions, peas, potatoes, radishes, rutabaga, spinach, and turnips. Leafy herbs also do well in winter, so plant chives, cilantro, dill, and parsley.
 
In mild winter climates, you can plant cool-weather crops under row cover or in the hoophouse to protect them from frost. Their growth won’t be as quick as in spring because of the declining day length, but you will be able to harvest many vegetables this fall and winter. Leafy greens and root crops are easy at this time of year. Plant arugula, beets, carrots, collards, kale, lettuce, onions, radishes, spinach, and turnips.

And if you’re in a region where hard freezes are common, you can still plant under row cover and overwinter crops that will be ready to harvest early in spring. Onions and spinach will do just fine in most places, given appropriate protection. A hoophouse or Quick Hoops (see Product Spotlight at right) will give you a harvest a month ahead of spring-sown crops next year.

Harvesting the final crops

Many crops will be fine, or even improve, with light frost. Those include most root, leaf, and flower bud vegetables: artichokes, beets, broccoli, Brussels sprouts, cabbage, carrots, cauliflower, chard, collards, kale, lettuce, mustard, onions, parsley, spinach and turnips.

If your markets will be ending soon, you might want to top your Brussels sprouts plants to get a uniform harvest of the sprouts that remain. A week before your expected first frost, cut the growing tip out of each plant. But if you want to keep them producing well into fall, leave them untopped. Their flavor is improved by cold weather and in milder areas, you will be able to pick into December – perfect for holiday markets.plant chives, cilantro, dill, and parsley.
 
The last of your warm-weather crops may still have harvest potential. Here are some ideas for plants that are likely to still be productive:

Peppers will slow down with the shorter days and cooler temperatures, so pick off any small ones that aren’t likely to mature before first frost. The remaining peppers will size up faster. When frost threatens, pull up chile pepper plants and hang them in a warm, well-ventilated area so the chiles will dry.

Winter squash will not ripen after being picked, so you have to protect the entire plant from early frosts if you have a large number of immature fruits. Sprinkler irrigation can be used to protect fruits from light frosts. Mature fruits can withstand one or two light frosts, but too much frost can cause spotting and poor storage.

Tomatoes will ripen and can be labeled “vine-ripened” if they have reached at least the breaker stage – pink on the blossom end – when they are picked. The ripening stages of tomatoes are immature, mature green, breaker, pink, and red. Mature greens are identified by a white to yellow star on the blossom end, and they also may ripen if they are kept dry and above 50°F/10°C. That’s the stage when most commercial tomatoes are picked for shipping.

Garden cleanup

Once crops have been harvested, it’s time to clean up the remains. Field sanitation consists of plowing down, composting, or otherwise removing plant debris, and mowing adjacent areas. Flowering plants can be left to provide seed for birds, but otherwise plants should be removed from the soil surface to prevent overwintering of pests and diseases. If you had a specific pest problem this season, do some research on the life cycle of the pest to determine where it is overwintering, and take appropriate action to deprive it of those conditions. For example, tarnished plant bugs – a serious pest of strawberries – overwinter as adults in leaf piles and wood piles, so don’t leave those near your strawberry field.
 
Most plant diseases will be killed by hot composting to 160°F/71°C. However, plant pathologists are recommending that plants with late blight be removed from the farm altogether to prevent the inoculum from overwintering.

Weedy areas adjacent to crop fields should be mowed because many kinds of vegetable pests are known to overwinter in them. These include armyworms, cutworms, crickets, earwigs, flea beetles, grasshoppers, lygus bugs, slugs and snails, stink bugs, thrips, and certain viruses vectored by aphids and leafhoppers. (Source: Pests of the Garden and Small Farm by Mary Louise Flint, University of California, available from Growing for Market.)

Reviewing records

Now is the time for a preliminary records review, while details are still fresh in your mind. In theory, you have been keeping planting and yield information all season, so you can go back and add comments about other aspects of the varieties you grew. Did your customers like it? Did you sell out, or did you have too much? Was the variety quicker or slower to mature than you expected? Was it better or worse than comparable varieties? Write down everything you can think of that will help you decide what to plant, and how much to plant, next year.
 
You should also have sales records for your crops, so do your tallying soon. When you see how much money you made on a crop – while you’re remembering how difficult it was to grow – you’ll make better decisions later about whether to grow it again, try a different variety, or drop the crop altogether.

If you sell to wholesale accounts, go back through your invoices and be sure you got paid for everything you delivered. You’re more likely to collect an unpaid invoice if you deal with it sooner rather than later.

Finally, try to get at least a ballpark figure of what you earned. You’ll have to pay taxes soon, so you need to plan for that final expense of the season.

Extend your season this fall, or get an earlier start next spring with a crop of succulent spinach. ‘Tyee’ is recommended for fall planting. In mild areas or in a hoophouse, individual leaves can be harvested beginning in about five weeks and continuing all winter. In cold areas, it can be grown outside under row cover and overwintered for an early spring harvest.

‘Tyee’, the standard overwintering variety, is savoyed with an upright growth habit that keeps leaves clean. It is the most bolt-resistant savoy type, so overwintered crops will last longer in spring before going to seed.

Spinach gets sweeter and crisper with cold temperatures, and demand will be strong, so plant accordingly.

‘Napoli’ and ‘Nelson’ carrots

‘Napoli’ and >’Nelson’ are two carrot varieties that are popular for fall planting and harvest. Both are Early Nantes types, which means they are medium length and cylindrical, are 56-58 days to maturity, and better for fresh eating than storage. In his book >The Winter Harvest Handbook, Eliot Coleman recommends both varieties for winter production. Here’s the difference between them:

‘Napoli’ is the variety Coleman uses for his “candy carrots,” which are winter-harvested carrots with an extraordinary sweetness. At his farm in Maine, he plants them in late July and early August, both in the field and in the unheated hoophouse. The field plantings are harvested in October and November, and the hoophouse plantings remain in the soil for harvest in December, January, and February.

‘Napoli’ is available as organic raw seed, organic seed with pelleting approved for organic use, nonorganic raw seed, as well as nonorganic seed with conventional pelleting.

‘Nelson’ is the preferred variety for overwintering. Coleman plants it in late December and it is ready for harvest May 10. Though not as sweet as the winter carrots, ‘Nelson’ is a good choice for early production.

‘Nelson’ is available as nonorganic raw seed, nonorganic seed with pelleting approved for organic use, as well as nonorganic seed with conventional pelleting.

Quick Hoops Bender

Johnny’s is pleased to introduce the Quick Hoops Bender, a tool used to make hoops for low tunnels quickly and neatly. It is the result of a collaboration between Johnny’s Selected Seeds, Lost Creek Greenhouse Systems, and Eliot Coleman, who advocates the use of Quick Hoops in his new book, The Winter Harvest Handbook. Coleman notes that three rows of Quick Hoops cover the same area as a 22 x 48 foot greenhouse, at 1/20th the cost. He uses Quick Hoops to overwinter onions, lettuce and spinach, which will be ready for harvest a month ahead of the earliest spring-sown crops.

Low tunnels are widely used on vegetable farms for a variety of reasons – they are covered with heavyweight row cover for frost protection, with lightweight row cover for insect protection, and with shade cloth to extend cool-loving crops into summer. Most growers have been using hoops of PVC conduit or coiled wire for their low tunnels. But those don’t hold up well to wind and snow, so they aren’t usually used to overwinter crops.

The Quick Hoops Bender, however, is designed to create hoops out of galvanized electrical conduit (EMT), which is much stronger and can take snow loads. These hoops can be pushed into the soil about 10 inches and covered with spun-bonded row cover in fall and then with greenhouse covering in winter. Both coverings are available in compatible sizes from Johnny’s.

The Quick Hoops Bender can be used to bend galvanized electrical conduit from ½ inch to 1 inch, and even 1-3/8 inch galvanized fence pipe. For most applications, ½ inch conduit is recommended. It is available in 10-foot lengths at home improvement stores for about $2 each. The Bender should be attached to a strong surface, such as a workbench or picnic table. Conduit is then fed into a holding strap and the operator manually pulls the conduit into shape around the bender. A hoop takes about a minute to bend. Detailed instructions and a video are available at www.johnnyseeds.com.

The Quick Hoops Bender comes in two sizes: #9520 creates hoops that are 6 ft. wide and 3 ft. tall (before insertion into the ground), which can cover two 30-inch-wide beds with a footpath between them; #9377 creates hoops that are 4 feet wide and 4 feet tall (before insertion), wide enough to span a single 3-foot bed and tall enough to be used for most summer crops.

The Quick Hoops Bender is available now, at $69 for either size. In the next few months, Johnny’s will introduce an optional trailer hitch mount for a farm vehicle, so the hoops can be bent right in the field where they will be used.

Download a printable PDF here.

So this was my garden a few weeks back, on August 28th. September pictures are to come!

The garden, probably at maximum growth.

The potatoes are still going strong, in late August!

I have picked about 20 pounds of pole beans so far this year. We’ve eaten many, I’ve shared many with relatives, I froze a few, and canned 15.25 pints of dilly beans. I’ve put my husband to work picking.

I will grow Fortex and Marvel of Venice again!

The Red Noodles are getting started – it seems that the ants have a symbiotic relationship with their flowers – they must be sweet.

Of course, the beans have had their share of pests. This is the Mexican Bean Beetle, sinister cousin of the familiar Ladybug. It feasts on bean leaves and beans, rather than the aphid pests enjoyed by red ladybugs.

The fuzzy larvae are bright yellow and easy to spot. They make a satisfying pop when you squeeze them between a folded bean leaf.

They do some damage to leaves and beans (the brown spots), but they aren’t bad enough for me to bother spraying for them. I’m sure if I were selling my produce I would do more to prevent them, but instead I just kill them when I can, and throw any beans with brown spots into the compost bin.

And, speaking of pests, here’s a weed pest: the insiduous Purslane. As Brian mentioned a few weeks back, pulling it and leaving it around won’t help – it will self-seed because its succulent leaves will keep it alive, even when pulled up. So discard somewhere safe – or you could eat it; it is edible, but you’ll want to read up on that first.

The cucumbers are doing fairly well – I have heirloom lemon cucumbers (named for size and color, not flavor) and a couple of varieties of pickling cucumbers growing.

My Baby Bear pumpkins are ripening!

I mixed up some seedlings – Honey Bear squash, a bush plant, is growing under the trellis. I have a couple of nearly ripe fruit – they are small, fist-sized acorn squash – a meal size of one per person.

The Zephyr summer squash and a vining variety – probably spaghetti or butternut – are doing quite well. I’ve shared quite a few summer squash, along with the beans.

Pepper plants are coming along!

These are Islander peppers – they are purple and will eventually turn red, if we have enough summer.

The eggplants are blossoming at last!

Some of the onion tops have fallen over and are ready to harvest. These are Walla Walla Sweets.

This is fennel, not dill – and it seems to be doing quite nicely.

The sweet potato vines are growing like the dickens – I am looking forward to digging them up. I think I’ll try to keep some vine cuttings alive in water over winter, for next year; they would be about the same as the slips I got this spring in the mail, but possibly more suited to my garden.

The tomato plants are coming along – not quite as large as I’d like them to be, but it could be worse – I could have late blight.

The Sungolds have been nicely productive all summer.

Early Girl tomatoes are reaching “breaker” stage – where they turn yellowish before they ripen to red. At this point, I could bring them indoors to ripen (in a paper bag or on the counter – the windowsill is actually not the best place to ripen tomatoes, I’ve read. That doesn’t mean I don’t put some there, anyway).

And the intrepid volunteer Wonder Light tomato plant is taking over the lawn.