The best time to sow outdoor vegetable crops

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The best time to sow outdoor vegetable crops
The best time to sow outdoor vegetable crops

A wedge of vegetable crops is always allocated in the garden, the main part of vegetable crops. Each crop has its biological characteristics, formed in the climate of its origin. The main condition for the successful cultivation of vegetable crops in non-native environments is the sowing period related to soil and air temperature, light intensity, and sunlight duration.

The article suggests becoming familiar with the approximate sowing dates of seeds of major outdoor vegetable crops in the open field in regions with different climatic conditions.


SOIL TEMPERATURE IS THE MAIN INDICATOR FOR SOWING

Soil temperature at a depth of the main block of the roots of a given crop is an indicator of the start of sowing. Its variability and rate of warming are influenced by snow cover, groundwater, soil type, and moisture content. Precisely, soil warming in the root dwelling layer provides the opportunity to obtain an early harvest.

If seeds are sown in cold soil, even cold-resistant crops may germinate but not form a crop. The root system cannot function properly in cold soil and cannot provide conditions for developing the above-ground parts.

To keep crops growing, heat-loving crops should be sown only if the weather is consistently warm and there are no return frosts. When they are threatened, cover the seedlings with any cover material (spindle, crop cover nonwoven) and remove them the next morning as warmer weather arrives. Solar heating of the mulched bed may adversely affect seedlings and young plants.

Naturally, the sowing dates for each region may not match the numerical data for spring and summer. Therefore, in areas with short warm periods and early cold periods, the main guidelines for open field seeding will be soil temperature, light intensity, and the establishment of a frost-free period.

A stable recommended soil temperature for several days is the signal to start sowing. In order not to sow vegetables in cold soil, different methods are used to determine the temperature of the root zone.


SOIL TEMPERATURE MEASUREMENT WITH A THERMOMETER

For this purpose, professional versions of crank thermometers, hood thermometers, and thermometer-sensors are used.

For novice gardeners, it is easier to determine the temperature of the soil layer by layer with a thermometer. Remember that they are used only during warm periods when the temperature at a depth of 2inch (5cm) drops to 32°F (0°C) – dig them out and bring them indoors. The method of measurement is specified in the recommendations.


MEASUREMENT OF SOIL TEMPERATURE BY PLANTS

The condition of the canopy, the above-ground parts of shrubs, the flowering period of perennial weeds should be taken into account.

Please record.

  1. The buds of black currant have unfolded and can be sown with vegetable and flower crops.
  2. The shoots at the birch beard are unfolding, which means that the soil at a depth of 2inch (5cm) is well heated, and it is time to sow early vegetables and plant early potatoes. Leaves are unfurling – time to sow radishes, carrots and other root crops. Prepare birch trees for flowering – the soil has warmed up to a depth of 4inch (10cm). Now is the time to sow tomatoes in the clearing.
  3. Dandelion flowering – the temperature in the 4inch (10cm) layer of soil is heated to 42-46°F (6-8°C), while in the 4-16inch (10-40cm) layer – only 37°F (3°C).
  4. When bird cherry blossoms are in full bloom, it is time to plant potatoes.

DETERMINATION OF SOIL TEMPERATURE BY PHYSICAL STATE

This method is more often used by experienced gardeners. A handful of soil is squeezed into a lump. If the surface of the lump behaves like a liquid – too early for sowing, and a crumpled lump – too early for sowing. If the lumps of soil fall off and fall apart into lumps, it is time to sow early cabbage and potatoes, salads, radishes.


LIGHTING IS THE SECOND MOST IMPORTANT INDICATOR TO START SEEDING

Light is the next most important condition on the list. It is governed by additional requirements: seeding time, air temperature, standing density, timely thinning, and elimination of tall weeds that shade plants.

Each type of plant usually has a certain amount of daylight hours for growth and development under natural conditions.

For some crops, the length of daylight does not affect the germination and development of the plant. Such crops can actually be sown throughout the warm season. Others are quite sensitive to changes in light. When selecting new varieties, breeders always adapt them to the climatic conditions of a particular region and accordingly recommend indicative sowing dates, which must be observed.

Groups of crops with different responses to light

Neutral

This group of crops is practically unresponsive to the amount and period of solar energy received. They include peas, beans, some varieties of tomatoes and cucumbers, as well as watermelons, asparagus, and others. This list is constantly being added to by breeders who “graft” the ability to not respond to the length of daylight onto new varieties and hybrids.


Short day

Under short daylight conditions (10-14 hours), plants bloom faster and go into fruition. These are certain varieties and hybrids of tomatoes, beans, cucumbers. Other squash (zucchini, squash, Pattison), corn, sweet and hot peppers, and eggplant are also included in this group. This group of green plants (dill, parsley, lettuce, spinach, sumac, green feathers of onions) is rapidly coming into flowering (blooming).


Plants with long sunlight

Plants in this group are entering the flowering and fruiting stage under sufficient light hours (more than 14 hours). This group of plants includes all types of cabbage, radish, turnip kale, special northern varieties of radish, Parsnip, carrots, beans, and beets. If long-day plants are given short-day conditions, early sowing or shade is used, their development will be hindered. They will not be able to enter the flowering and fruiting stages. It stops at the formation of lush rape flower clusters (asexual organs).


SOWING TIME FOR OPEN-FIELD VEGETABLE CROPS

Sowing time for open-field vegetable crops
Sowing time for open-field vegetable crops

Early spring sowing (mid-March – mid-April)

Cultivars with low and medium light requirements make up this group of plants. Sowing of early spring greens and vegetables can be done in stages, 10-12-15 days, which prolongs the reception of fresh produce.

List of crops sown in a 3-4inch (8-10 cm) layer with soil temperatures in the range of 37-41°F (3-5°C).

  1. Green (pungent) – dill, parsley, cilantro, fennel, parsley, mustard leaves, celery, asparagus, melissa, and others.
  2. Vegetable leafy and above-ground crops – all types of salads, horseradish, spinach, rhubarb, peas, early cauliflower, broccoli, early cabbage.
  3. Onion and root crops. Sow onions and leeks, early carrots, radishes, turnips, rutabagas.

Mid-spring sowing (mid-April to the second decade of May)

If the spring is cold and wet, sowing is delayed (5-8 days). In addition to cold resistance, these crops can be sown in stages over 10-12-15 days, which will extend the time to receive fresh produce.

As the soil in the root zone warms from 41°F (5°C), you can continue to sow some crops that require less and moderate sun conditions.

List of crops to sow in the 3-6inch (8-15 cm) soil temperature range of 41-46°F (5-8°C).

  1. greens – leaf celery, petiolar celery, root celery, salad chicory.
  2. Vegetables – all types of cabbage: Cabbage, red cabbage, Brussels sprouts, Savoy cabbage, kohlrabi, etc. Are sowing early and middle potatoes, leeks, spring garlic. Sowing onions and beans, beans have been sown. Near May, sunflowers and vegetable corn were sown.
  3. Root crops: Beet, medium carrots.

Late spring sowing (last decade of May – mid-June)

The sowing of open field vegetables took place in the third decade of May-June when the weather was consistently warm and without return frosts. For example, in the middle belt, the western part of the USA, warm weather without frosts was established after end of March. The soil in the root-dwelling layer warmed up to 53-59-62 °F (12-15-17 °С). This means that even open field sowing of early cold-resistant vegetable crops is shifted to pre-summer or early summer.

In these areas, it is more appropriate to use early varieties, be sure to zone them according to the local climate, use temporary shelters and replant vegetable crops in protected areas during autumn.

Temperature-loving crops sown at soil temperatures up to 53-59-62 °F (12-15-17 °С) in the 3-4inch (8-10 cm) layer
Sowing of tomatoes, beans, cucurbits (melons and watermelons), sunflowers, basil, marjoram, root crops (carrots, beets) when stable warm periods come. The shoots of the lycopodium family (tomatoes, eggplants, bell peppers, and peppers) and squash crops (cucumbers, zucchini, and pumpkins) were planted in the open ground.

Thus, experts identified plant groups requiring certain soil temperatures, frost-free weather, and the amount and duration of solar energy for germination and normal development.


CHARACTERISTICS OF SELECTING VEGETABLE SOWING DATES IN DIFFERENT REGIONS

When choosing the time for sowing vegetables on the plot, it should be taken into account that some short-sun varieties require a dark factor, but only at the beginning of the growing season (during this time they are shaded). As they age, they develop normally and form fruit under long daylight conditions. If short-day plants receive more than 14 hours of sunlight, their development slows down and their nutrient bodies begin to concentrate. This property is used for roasting vegetables to produce fresh and early vegetables quickly.

In cold regions, shifting the sowing of vegetable crops to the early stage, it is necessary to use temporary sheds and prepare warm beds.

The Far East has a special temperature regime. Vegetable cultivation is concentrated in coastal areas. Wet, warm summers allow producing quite high yields of cold-resistant varieties of bell peppers and cucurbits, which were bred especially for this region, as well as cabbage and carrots, which can be sown after mid-June, i.e. in early summer.

Green production of pungent vegetables grown in the open field can be obtained only when sown in summer. In these areas, it is more appropriate to use early maturing varieties, always zoned according to the local climate, using temporary shelters, and replanting vegetable crops in protected areas during the fall.

Replanting vegetable crops in protected areas during the fall
Replanting vegetable crops in protected areas during the fall

Table 1: Sowing dates in the southern region

Crop nameOpen field early spring crop (March-April)Open field mid-spring crop (April-May)Open field late spring crops (May-June)
Dill, fennel, parsley, celeryMarchJune
LettuceMarch-AprilApril-May
Chives, Leek, onionsMarchApril
CucumberAprilMay
Spring garlicMarch
PotatoesMarch-Aprilfrom April (medium maturing varieties)
CarrotsAprilApril-MayMay-June
RadishMarch
ParsnipAprilApril-May
PeasMarch
Sweet cornApril-May
BeansMay
BeetAprilAprilMay-June
TomatoesMarchApril (medium-ripening varieties)
Eggplant, bell peppers, and peppersAprilMay-June
CabbageMarch (early and medium maturing varieties)April-May (late-maturing varieties)
Zucchini, squashApril-May
Watermelon, melon
Sowing dates in the southern region

Table 2: Sowing dates in the central region

Crop nameOpen field early spring crops (March-April)Open field mid-spring crop (April-May)Late spring crops in the open field (May-June)
Dill, fennel, parsley, celeryMarchApril-MayMay-June
LettuceMarch-AprilAprilMay
Chives, Leek, onionsMarchApril-MayJune
CucumberApril-MayMay-June
Spring garlicMarchMayMay-June
PotatoesMarch-AprilMayMay
CarrotsMarch-AprilApril-MayMay
RadishAprilApril
ParsnipMarchApril-May
PeasAprilAprilMay
Sweet cornAprilMay-June
BeansMay
BeetMarchApril-MayMay
TomatoesApril (coverings)April-MayMay-June
Eggplant, bell peppers, and peppersApril (coverings)April-May (coverings)May-June
CabbageMarch (early variety & mid-ripening variety)May (mid-ripening variety)May (mid-late variety)
Zucchini, squashMay
Watermelon, melonMay
Sowing dates in the central region

Table 3 Sowing dates in the eastern region

Crop nameOpen field early spring crops (March-April)Open field mid-spring crop (April-May)Late spring crops in the open field (May-June)
Dill, fennel, parsley, celeryResowing in March & AprilMayMay-June
LettuceMarch & April reseedMayMay-June (cover)
Chives, Leek, onionsAprilMayMay-June (coverings)
CucumberMay (covered in a warm bed)June
Spring garlicAprilApril
PotatoesApril (covered)April-MayMay (early varieties)
CarrotsMarch (early varieties) & April (medium varieties)April-May (medium varieties)May (late varieties)
RadishMarchMay (shade due to longer daylight hours)May-June (shade)
ParsnipMarch
PeasMarch-April (coverings)MayJune
Sweet corn
Beans
BeetAprilMay
Tomatoes
Eggplant, bell peppers and peppers
CabbageMay (early variety coverings)May
Zucchini, squashJune
Watermelon, melonJune
Sowing dates in the eastern region

Table 4: Sowing dates in the western region

Crop nameOpen field early spring crop (March-April)Open field mid-spring crop (April-May)Open field late spring crops (May-June)
Dill, fennel, parsley, celeryApril-MayMay-June
LettuceApril-May (cover crops)June (cover crops)
Chives, Leek, onionsMayJune
CucumberMay-June (on warm beds or under temporary cover)May-June
Spring garlicMay
PotatoesApril-MayMay-June
CarrotsApril-MayMay-June
RadishMay-June (coverings)
Parsnip
Peas
Sweet corn
Beans
BeetMayMay
TomatoesApril-May (coverings)
Eggplant, bell peppers, and peppers
CabbageMay (early varieties, coverings)June (coverings)
Zucchini, squash
Watermelon, melon
Sowing dates in the western region

Table 5: Sowing dates in the northwestern region

Crop nameOpen field early spring crops (March-April)Open field mid-spring crop (April-May)Late spring crops in the open field (May-June)
Dill, fennel, parsley, celeryMayMay-June
LettuceMay (coverings)June (coverings)
Chives, Leek, onionsMayJune (coverings)
CucumberMay-June (in warm beds or under temporary cover)June (open spaces)
Spring garlic
PotatoesApril-May (early maturing varieties)May-June
CarrotsApril-MayMay-June
RadishMay (coverings)
Parsnip
Peas
Sweet corn
Beans
BeetMay
TomatoesApril-May (coverings)
Eggplant, bell peppers, and peppers
CabbageMay (early varieties, coverings)June (coverings)
Zucchini, squash
Watermelon, melon
Sowing dates in the northwestern region

Table 6: Sowing dates in the northeast

Crop nameOpen field early spring crops (March-April)Open field mid-spring crop (April-May)Late spring crops in the open field (May-June)
Dill, fennel, parsley, celeryMayMay
LettuceMayMay
Chives, Leek, onionsMayMay
CucumberMay (coverings)May-June (coverings)
Spring garlicMayMay
PotatoesMayMay
CarrotsMayMay-June
RadishMayMay (coverings)
ParsnipMay
PeasMayJune
Sweet cornMay
BeansMayJune
BeetMayMay
TomatoesApril-May (coverings)
Eggplant, bell peppers, and peppers
CabbageMay (early varieties with coverings)
Zucchini, squashMay (coverings)May-June
Watermelon, melon
Sowing dates in the northeast

CONCLUSION

Dear readers
This article provides indicative data on open field sowing. The main criteria for sowing time, regardless of the region of the country, are the specified soil temperature, the beginning of the frost-free period, the intensity of sunlight. If you have other self-explanatory guidelines and methods, please write them in the comments. This is a very interesting and necessary material for the reader.

More related information about growing vegetable

Title: The best time to sow outdoor vegetable crops
Source: ThumbGarden
Link: https://www.thumbgarden.com/outdoor-vegetable-crops/
The copyright belongs to the author. For commercial reprints, please contact the author for authorization, and for non-commercial reprints, please indicate the source.

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