Harvesting vegetables

Guidelines for optimum harvest

Harvesting vegetables may seem like a simple task. "You just pick them when they look right". However, the goal is to harvest vegetables when they are at their best - the most tender and sweetest. A number of vegetables if not picked at the optimum time become stringy, woody, or tasteless, which cancels out the hard work put into planting and taking care of them. It's always advisable to harvest when it's cooler, such as evenings or early mornings, since plants tend to be at their best and will maintain that vigour and sweetness longer. Once plants are harvested, it is critical to cool them off as quickly as you can to significantly extend freshness - don't hose off those carrots and leave them lying in the sun for the afternoon if you expect them to stay sweet for long!

Here are a few guidelines to ensure that vegetables are harvested at their optimum.

ASPARAGUS

If plants were started from root crowns, you may be tempted to harvest in the second year, although it's advisable to wait until the third year. Plants that are started from seed, require at least 3 years before the harvest of the spears. The spears may be harvested over a 2 week period during the third year. In the fourth and subsequent years, harvest may be extended to four or more weeks. Cut a spear about 1 inch (2.5 cm) below the ground when the spear's length is about 7 inches (17.5 cm). This will give an edible shoot of 8 inches (20 cm). Crowns may be easily damaged by the knife, so some people prefer to break off the spears at soil level. Eat asparagus immediately, or store them by immersing the cut ends in water and refrigerating. Once well established, this perennial vegetable can be harvested for a period 6-8 weeks each spring.

BEANS

Green beans indicate maturity by the smoothness and greenness of the pods. Snap beans are ready to pick if they snap easily when bent in half. Once pods begin to turn yellow and the beans start to become apparent (a corrugated look), the snap beans will be tough. Yellow beans varieties should also be picked before they appear corrugated. Days to maturity for beans are: bush beans, 50-60 days; pole, 60-90 days; limas 80- 100 days.

BEETS

Beets may be harvested as soon as they reach 1 inch (2.5 cm) in diameter. They are excellent at 2 inches (5 cm), but over 3 inches (7.5 cm) they become tough. The tender inner leaves can be used for pot greens. Beet greens make excellent borscht (beet soup).

BROCCOLI

Cut broccoli when the individual buds in the clusters are still tight. Once buds open, the broccoli has a stronger flavour. The first crop will consist of the central head with 5 inches (12.5 cm) of stem. A second crop can be harvested for several additional weeks, consisting of side shoots that have 3-4 inches of stem. Broccoli should be picked every 3-4 days so the crop does not get out of hand. (Any surplus broccoli can be frozen once blanched).

BRUSSELS SPROUTS

For a better harvest, snip off the top 3 cm (1 inch) of the plant in late August to encourage the side sprouts to grow. You may start picking the lower sprouts when they are between 1 to 1.5 inches (2.5-4 cm) in size. Sprouts should be bright green and firm. If the weather stays cool, one could expect 100 of these "tiny cabbages" per plant. Don't harvest too early - Brussels sprouts hit by a light frost tend to be less bitter / sweeter tasting.

CABBAGE

These may be harvested as small as 4 inches (10 cm) in diameter and continued until 6-10 inches (15-25 cm). The heads should be firm at harvest, but don't wait too long. A prolonged harvest may result in split heads. Maturity may take 2-3 months, depending on the year.

CARROTS

Tiny sweet carrots can be harvested at 3-4 inches (7.5-10 cm) long. The remainder can be allowed to grow to about 1 inch (2.5 cm) in diameter. Once the carrots reach 1 1/2 inches (4 cm) or larger, they will be woody. Maturity time from seed to harvest is 65-80 days depending on the carrot variety and environmental conditions such as weather.

CAULIFLOWER

The head is made up of small segments resembling cottage cheese curds. For the best flavour, these segments should be tightly packed, white or ivory in colour without brown spots present. When the heads start to form, tie the leaves together at the top to form a teepee. This will keep the sun out and prevent the head from yellowing. Transplant to harvest time is approximately 70-80 days or up to 100 days if cool weather persists.

(SWISS) CHARD & SPINACH

Pull off outer leaves as they mature, making sure to leave a central tuft of leaves to maintain the plant. Chard leaves are best harvested when they are 6-10 inches (15-25 cm) long and spinach 4-6 inches (10-12.5 cm) long. Swiss chard and spinach need 45-65 days to mature.

CORN

Harvesting corn at the right time can be vitally important when it comes to flavour. The first thing to watch for is pollination which is indicated by clouds of pollen erupting when you walk through the corn patch. About 3 weeks later, the silk will turn brown. Maturity can be tested by peeling down the husks at this time. Pop a kernel 2 inches (5 cm) from the top end of the ear with your fingernail. If the fluid is watery, it is still too early and you will want to wait a few more days; if the fluid is milky, the corn is at the right stage for eating; but if it is the consistency of toothpaste the corn has gone starchy and would be best used as creamed corn or used in chowders. The milky kernel only lasts for a few days so you don't want to delay harvesting.

After picking the cobs, cool them as quickly as possible, by plunging the ears into ice water and store in the refrigerator. Once cobs are picked, they immediately start changing sugars into starches, especially in warm temperatures. Corn requires 65-90 days to mature, depending on variety and environmental conditions.

CUCUMBERS

Cucumbers should be picked when they are still green and about 3 inches (7.5 cm) long for sweet pickles, 6 inches (15 cm) for dills and 8 inches (20 cm) for slicing. Picking 4-5 times a week will encourage continuous production. Do not leave mature fruit on the vine. Cucumbers are past their optimum stage once they turn yellow, form a tough skin and have tough seeds. Days to maturity vary between 55-70 days.

GARLIC/LEEKS/ONIONS

Green onions are best harvested when the stem reaches the thickness of a pencil. Leeks are harvested when the stem diameter reaches 1/2 - 1 1/2 inches (2-4 cm). Garlic is ready to be pulled when 1/3 of the top has died back.

Bulb onions may be gathered as needed or when tops start to bend over and yellow. If they are still actively growing by the beginning of September, the tops should be bent over to start a bulb curing process. Onions should not be subjected to a heavy frost or the bulbs will be ruined. If they do not cure on their own or conditions are not favourable for outdoor drying, they may be spread out on the floor in a warm dry building preferably with a forced flow of warm air.

Garlic requires a curing period of about 20 days at 20 degrees C (or 10-14 days at 27 degrees C) with a lot of air movement.

LETTUCE

The outer leaves should be harvested before yellowing or browning occurs. If the stand is thick, entire plants may be cut off, allowing the remaining plants more room to develop. Head lettuce should be firm before it is picked. In semi-heading types the centre will not become firm, so you may harvest as soon as a soft head forms. Leaf lettuce is ready to eat 40 days after seeding. Approximately 100 days are needed for large heads to form.

PEAS

Harvest the pods just before they appear round in cross section, while retaining their bright green colour. Chinese and snow peas, whose pods are eaten, are picked when pods are flat and about 1.5-2.5 inches (4- 6.5 cm) long. Pods longer than 3 inches (7.5 cm) are too fibrous. (Pick the pods carefully so as not to break the the vines and do not leave overripe pods on the plants.) Pods can be picked 60 days after planting.

BELL PEPPERS

Peppers may be harvested with a sharp knife; at any size when the fruit is dark green. If you would like a few red peppers for a nice colour contrast in salads, allow some of the fruit to remain on the plant until it turns red. Maturity time needed for transplants is between 75-85 days. Small peppers grow slowly so you will need 6-8 weeks from seed to transplant size.

POTATOES

For fresh tasting "new potatoes", dig up the tubers when the flowers form on the plant. For fully mature potatoes, wait until the top growth starts to die back. If you want to store the tubers for a prolonged period of time it's advisable to wait until the crop matures. Mature tubers will have a firm hardened skin, will be less susceptible to injuries and will store better than immature tubers. It is best to harvest before the first killing frost. If the growing season has been too short to mature the tubers naturally, the tops may be prematurely killed by cutting them, once tubers have reached an acceptable size. The skin will harden sufficiently if tubers are left 10-14 days in the soil.

PUMPKINS

Wait until the fruit is a deep orange. If you cannot sink your fingernail easily into the rind, the pumpkin is ripe enough to put directly into storage. By this time, the vines will usually be drying. If the pumpkin is not mature, it may be left on the vine until after a light frost. However, if the average daily temperature is below 15 degree C growth will be reduced or eliminated and the benefit of covering the plant will be questionable. If a heavy frost threatens and you must harvest earlier, leaving the pumpkin at room temperature for a few weeks will allow the rind to harden. Pumpkins may be stored at 10 degree C with 70 to 75 percent relative humidity.

RADISHES

Thinning and eating may start when radishes are the size of marbles. Radishes may harvested up to 1 inch (2.5 cm) in diameter; beyond that size they become pithy and strongly flavoured. Radishes mature 25-30 days after seeding.

SQUASH/ZUCCHINI

Common green zucchini is best harvested when 6-10 inches (15-25 cm) in length, yellow types at 4-7 inches (10-17 cm) and patty pan (scallop types) when 3-5 inches (7-12 cm) in diameter. Summer squash larger than this will develop hard skins and large inedible seeds. Spaghetti squash may be harvested when golden yellow and banana squash picked when golden orange. Winter squash are cut with a few inches of stem, after the vines have died back in late summer or fall. Skins should be hard enough to resist your fingernail. Frequent picking will encourage continuous production. Summer squash requires 50 days to mature, whereas winter types require 80-120 days.

TOMATOES

Tomatoes reach full flavour when uniformly red, but you may wish to pick some green tomatoes for frying. Overripe fruit may used for processing into juice, catsup or sauce. One can expect a full red colour to develop 5 days after the first signs of pink show on the fruit. If frost is approaching and you still have green fruit on the plant, pick the tomatoes with 2 inches (5 cm) of stem attached or pull the entire plant. Store in a cool dark place (inside a brown paper bag or under brown paper works well) and allow to ripen. Ripening time from large transplants until harvest will range from 55-75 days.

REFERENCES:

  • When to pick a vegetable, by Warren Asa.
  • Step-by-Step, Planting Asparagus, by Rosalie H. Davis.
  • Hortideas; September 1990.
  • Growing Garden Potatoes; Agriculture Canada; Publication 1559 E.
  • Harvesting and Storage of Onions, by D.H. Dabbs; Department of Horticulture Science; University of Saskatchewan; Saskatoon.
  • The Pumpkin Comes in all Shapes and Sizes, by Grant Wood; University of Saskatchewan.