Austrian Winter Pea

Root rot is not one organism but a group of soil fungi and water molds - Pythium, Phytophthora, Fusarium, Rhizoctonia and others - that sit harmlessly in most soils and only turn destructive when the ground stays saturated. Waterlogged soil drives the air out, the roots suffocate, and the weakened tissue is invaded and goes soft, brown, and stringy. Because the damage is underground you usually see it first as something that looks like drought: wilting, yellowing, stunting, a plant that does not respond to being watered. Overwatering, heavy compacted ground, a low spot that collects runoff, a pot with no drainage or a saucer left standing full, and cold wet soil in winter are the usual causes. Once roots have actually rotted there is no cure - this is a problem you prevent rather than treat.

Watch for: Wilting in the middle of the day on a plant whose soil is damp - the classic tell, and the reason people water a rotting plant and finish it off. Leaves yellowing from the bottom up, dull off-color foliage, and growth that stalls for no visible reason. Whole shoots, or one side of the plant, collapsing while the rest still looks fine. Soft, dark, or mushy tissue at the base of the stem or at the crown, sometimes with a sour smell. Lift a failing plant and look at the roots: healthy ones are firm and pale, rotted ones are brown or black and slimy, and the outer layer slips off between your fingers leaving a thread of core behind. Seedlings that topple over at soil level are the same problem, called damping-off.

Prevent: Drainage is the whole defense. Match the plant to the site first - something that wants sharp drainage will not survive heavy clay or a low, water-collecting spot however well you tend it. Where the ground is heavy, plant on a raised bed, berm, or slope, or grow in a container. Set plants at the depth they were already growing, since burying the crown or the root flare is a common cause of rot, and keep mulch pulled back a few inches from the stem base instead of piled against it. Water the soil rather than the calendar: check that the top inch or two is dry before watering again, cut back hard in cool weather and winter dormancy, and never leave a pot standing in a full saucer. Do not plant or dig in soggy ground, and go easy on rich amendments for plants that want it lean. Rotate annual crops, and start with clean healthy plants and fresh mix.

Treat: There is no cure for tissue that has already rotted, so act on the conditions rather than looking for a spray. Stop watering at once and fix the drainage - open up compacted soil, or move the plant to a raised, sharply drained position or a container. Lift a badly affected plant, cut away every soft dark root and rotted section with a clean blade back to firm pale tissue, and replant only the healthy parts into fresh free-draining soil or mix. Often the better move is to give up on the plant and save its offspring instead: cuttings, offsets, or divisions taken from firm healthy growth root readily and give you a clean start. Bin the rotted material rather than composting it, and correct the drainage before you replant, because the rot comes straight back in the same wet spot.

The commonest way a fall-sown winter pea stand is actually lost, and it gets blamed on cold: a mild wet winter on heavy ground rots the roots and crowns out while a colder, drier winter would have left the stand untouched. Sow on well-drained ground, and rotate away from peas, lentils and vetch.

Seed sold for agricultural cover-cropping is frequently treated with fungicide, and sometimes insecticide, before bagging. Treated seed is dyed a bright warning color - typically pink, blue, green, or purple - and is legally not food: it must not be eaten, sprouted, or fed to animals, and the bag tag will say so. This matters for cover crops whose growing parts are edible, because a gardener who buys a farm-store bag of peas, vetch, clover, or alfalfa may reasonably assume the resulting plants are food. Seed sold for planting is also not subject to the food-safety handling that seed sold for sprouting or eating is. The hazard is entirely avoidable and entirely upstream: it is decided at the moment you choose which bag to buy.

Watch for: Seed that is dyed pink, blue, green, or purple rather than its natural color - the deliberate industry warning, and the clearest sign. A bag tag carrying wording such as treated seed, do not use for food or feed, or a chemical name and EPA signal word. Dusty colored residue on your hands or on the bag. Seed bought loose or unlabeled from a farm store bin, where you cannot check the tag at all. Sprouting or shoot-growing seed sold in food packaging rather than farm packaging is the alternative you are looking for.

Prevent: Decide before you buy. If you intend to eat any part of the crop - pea shoots, sprouts, flowers, or seed - buy seed explicitly labeled untreated, or seed sold as food for sprouting, and keep the bag tag with the record of what you sowed where. Ask the supplier directly if the listing does not say; untreated cover-crop seed is widely available and usually costs no more. Never eat anything from a stand whose seed source you cannot account for, including a bed sown by someone else or from an unlabeled leftover bag. Store treated and untreated seed separately and clearly labeled so they cannot be confused a season later.

Treat: There is nothing to do to a stand already grown from treated seed except not eat it - grow it out as a cover crop, terminate it as green manure, and buy untreated seed next time for the bed you intend to pick from. The treatment is on the seed coat rather than systemic through the whole plant, but there is no home way to verify what was used or at what rate, so the only sound rule is to treat the whole stand as non-food.

The one genuine safety issue with growing this crop for its shoots, and the reason to buy untreated seed at the outset rather than discover the problem at picking time.

Birds find ripening fruit and seed before you do. Robins, waxwings, starlings, catbirds, jays, sparrows, finches, blackbirds, and doves all work a garden, and the pressure arrives in a narrow window - the last days before harvest, when sugar rises, color changes, and the crop softens or the grain hardens. A flock can strip a small planting in a day or two, and birds that only peck rather than take whole fruit still leave wounds that rot or draw wasps. Squirrels, chipmunks, and other wildlife usually turn up on the same crop at the same time. This is competition rather than disease: the birds are not harming the plant, and a big tree or a heavy-cropping bush often has enough for everyone - but on a small planting it can be the difference between a harvest and none.

Watch for: Fruit disappearing from the outermost, most exposed parts of the plant first, and from the top of a tree where you cannot reach anyway. Single neat pecks and gouges in ripening fruit, with several fruits sampled rather than one eaten through - the classic sign that it was birds rather than an animal. Heads of grain or seed going visibly lighter and emptier as they ripen, with hulls and chaff scattered underneath. Freshly sown seed vanishing off the surface of a bed before it germinates. Bird traffic in and out of the plant picking up as the crop colors, and birds waiting on nearby wires and branches. Wasps arriving at the pecked and split fruit shortly afterward.

Prevent: Net, and net early. Bird netting draped over a frame or hoops so it stands off the fruit, with the edges closed at ground level, is the only thing that reliably works at harvest scale - and it has to go on before the crop starts to color, because once birds have found the food they are far harder to displace. Keep fruit trees small enough that netting them is actually feasible; that decision gets made years earlier, at planting. Bags of mesh, organza, or paper slipped over individual heads, clusters, or prize fruit protect a small crop without netting the whole plant. Then shorten the exposure: pick promptly and completely rather than leaving ripe fruit hanging as a lure, clear split and dropped fruit that draws birds and wasps alike, and where a crop can finish off the plant, harvest a little early and ripen or dry it under cover. Rake in or cover broadcast seed so it is not lying in plain view.

Treat: There is no treatment once a crop is being taken - only protection and timing, so the answer is to get netting on and to pick what is ready. Reflective tape, flash ribbon, spinners, and decoy predators do work, but only for a few days at a time: birds habituate fast, so move and rotate them and never rely on them as the main defense for a crop you care about. Cut and gather grain or seed heads a little early, at firm dough, and finish drying them under cover instead of leaving them standing for the flocks. Plant a little extra, or a decoy crop the birds prefer, and accept sharing anything that crops heavily. On a wild or foraged patch, fruit going to birds and small mammals is the point of the plant rather than a problem to solve.

Two windows here. Doves, pigeons, and jays take the big peas straight off the surface of a freshly sown bed, which is the main reason to rake the seed in 1-2 inches rather than broadcasting it bare. Later, geese and doves graze a young winter stand hard in some gardens.

Powdery mildew is a fungal disease that coats leaves - and often stems, buds, and fruit - in a white-to-gray powder that looks like spilled talcum. It is not one fungus but a large family of them, each fairly specialised to its own group of plants, which is why mildew on one crop rarely jumps to an unrelated one beside it. Unlike most leaf diseases it does not need wet leaves: it thrives on warm dry days followed by humid nights, and it takes hold fastest where plants stand crowded in still air or in shade. The coating blocks light, so heavily covered leaves yellow, brown, and drop early. On many plants that is mostly disfiguring and arrives late enough not to matter; where it strips away the leaves a crop still needed to finish, it costs you size, sweetness, and quality.

Watch for: Round white powdery spots on the upper leaf surfaces that spread and merge until whole leaves look dusted. It usually starts on the oldest, lowest, most shaded leaves and works upward, so check there first. Look at the undersides too, and at stems, buds, and flower stalks, which get coated as it advances. Leaves that yellow, brown, curl, or go crisp and drop early under the coating. New growth that opens small, crumpled, or twisted where the fungus has reached the shoot tips. On plants where it gets onto the fruit, a dull gray film, russeted or scarred skin, and cracking. Late in the season, tiny dark specks scattered through the white felt - that is the fungus setting up to overwinter on the debris.

Prevent: Give plants room. Crowding and still air are the biggest single driver, so space at the full recommended distance, thin seedlings properly, and divide or prune out congested growth until air moves through the plant. Full sun and an open position help; deep shade and a still corner against a wall are where it always starts. Water at the base rather than overhead, and water early in the day so nothing stays damp overnight. Keep plants evenly watered - drought stress at the roots leaves them far more susceptible, even though the fungus itself likes dry air. Go easy on nitrogen, since soft lush growth is the most vulnerable. Where resistant varieties exist for what you are growing, choosing one is the single most effective thing you can do on a plant that mildews every year. Clear infected leaves and stems away at the end of the season rather than composting them.

Treat: Start early: sprays protect healthy tissue, they do not clean up leaves that are already coated. Pick off and bin the worst leaves as soon as you see them, and open the plant up by thinning or pruning so air moves through. On anything that regrows quickly, shearing the whole plant back forces a clean flush and beats spraying. If it keeps spreading, potassium bicarbonate, horticultural oil, or neem applied weekly will hold it - cover both leaf surfaces. Sulfur also works, but it burns the foliage of some plants, should never go on in heat, and must not be mixed with or applied close behind an oil spray. Whatever you use must be labeled for the plant you are treating: follow that label and observe its pre-harvest interval on anything you eat. Do not compost badly infected material. Late-season mildew on a plant that is finishing anyway is usually cosmetic; on a crop still filling out it is worth acting on.

On a winter pea stand this turns up in spring as the weather warms, usually alongside the heat that was about to end the crop anyway - so the answer is normally to terminate the cover rather than treat it. It does end the shoot-picking season, since mildewed tips are not worth eating.

The pea aphid is a large, long-legged, pale-green aphid that specializes on legumes - peas, vetch, clover, alfalfa, lentil, faba bean - and colonizes the growing tips, tendrils, flower stalks, and developing pods. It builds fastest in the mild weather of spring, when a handful of overwintered females can become a coating within two weeks, and it drops off the plant readily when disturbed. On a vigorous cover-crop stand the feeding itself is usually cosmetic and is held in check by the ladybugs, lacewings, hoverflies, and parasitic wasps that legume flowers attract. What matters more is that it transmits viruses between legumes, including pea enation mosaic and bean leafroll, which stunt and yellow a stand out of all proportion to the number of insects present.

Watch for: Colonies of large pale-green aphids packed onto shoot tips, tendrils, and flower stalks, thickest on the softest new growth. Aphids dropping off the plant the moment you brush against it - a habit fairly specific to this species. Sticky honeydew on the foliage below, ants running the stems, and white cast skins where a colony has been. Yellowing, stunting, downward-rolled leaves, or a mottled stand that does not grow away, which points to a virus the aphids brought rather than the feeding itself.

Prevent: Encourage the beneficial insects that legume flowers already draw, and skip broad-spectrum sprays that remove them. Do not over-feed nitrogen, since soft lush growth is what the colonies build on - and a legume should not be getting nitrogen anyway. Check the growing tips weekly through spring, and rub out the first colonies by hand while they are small. Where virus has been a recurring problem in a legume rotation, avoid planting a new stand immediately downwind of an old one, since that is how the winged aphids move.

Treat: On a cover crop, usually nothing at all - the predators arrive and the stand outgrows it. Knock heavy colonies off with a jet of water, or pinch out and remove the worst-infested tips. Insecticidal soap sprayed directly onto the insects works if a stand is genuinely being checked, but it also hits the beneficials, so keep it to spot treatment. Never spray a stand you intend to pick shoots or flowers from without checking the product label for that use and its pre-harvest interval.

Worth knowing about mainly because the shoot tips the aphids colonize are exactly the tips you were going to pick and eat. Rinse shoots well, and pick past a colonized tip rather than spraying a crop you are eating raw.

A seedling rot that collapses young desert marigold seedlings sown too thickly or kept too wet in cool conditions - a minor issue easily avoided by lean, well-drained sowing and careful watering.

Watch for: Seedlings that fail to emerge or collapse at the soil line soon after germinating, and thin, patchy establishment in cold wet conditions.

Prevent: Sow into warm-enough, well-drained, moist (not soggy) soil with good seed-to-soil contact, and don't sow too deep or too early into cold ground.

Treat: None for affected seedlings; reduce watering, improve drainage and airflow, and resow more thinly if needed.

An establishment problem here rather than a season-long one: sow into a moist, well-drained bed while the soil still has some warmth, and it rarely appears.