Organic Vegetable Gardening

The vegetables

Most crop failures are the result of poor soil preparation, overcrowded plants, neglected weeding or insufficient watering. If you get these four things right there will be plenty in your garden to stuff yourself with even if you treat all vegetables alike. Beginning to consider the special needs of different vegetables in your garden is the next step. It can further increase yields and improve flavour and quality. Knowing your plants is especially important when you grow plants that are not well adapted to local conditions.

Here I describe how to succeed with some of the vegetables that I have grown in my garden. Most of the vegetables included are fairly easy to grow, but there are also a few personal favourites that are not so easy.

The figures on yields, sowing temperature, spacing etc. are typical for the particular vegetable, but may vary depending on variety. Development time is the time from sowing to first harvest in Stockholm for the range of varieties that are available here. In warmer climates development will be a little faster.

The sowing temperatures recommended are the averages of mean daily maximum and minimum air temperatures. To translate these temperatures to sowing dates you will need information on the mean daily max and minimum temperatures where you garden. The World Meteorological Organization is a specialized agency of the United Nations and provides climatological data for many locations worldwide. The site also provides links to the National Meteorological Services of the 185 States and Territories that are Members.

Daily mean and daily maximum temperatures are important for seed germination, but for frost sensitive vegetables the daily minimum temperature is often more critical. In my garden the risk of frost is past at the beginning of June when the mean daily minimum temperature reach 8^oC.The climate in my garden is very much influenced by the baltic sea which acts as a buffer against temperature extremes. In most regions the difference between day and night temperatures is greater. Even if the summer climate is much warmer where you garden, the risk of frost may be equally large.

Summer Squash: This vegetable is very easy to grow and even the most incompetent gardener will get a decent harvest. Squash grows best in well fertilized soil. The yield per sqm will be between 10 and 30 kg. Some varieties trail over the ground and the required spacing may vary. They can also be trained up trellises or other supports. Bush varieties require less work, and the spacing between plants should be 50-60 cm in all directions. The seeds are large and should be buried at a depth of three cm. They need a daily mean air temperature of at least 12 degrees C to germinate. If seeds are sown to early they will rot. Frost kills the plants instantaneously and I protect my plants with portable cold frames until they get to big. To much water during the first 50 days will lead to excessive production of leaves and delayed maturation, but when plants flower they need more water. Drought causes blooms and emerging fruits to fall of which reduces the yield. In Stockholm the first fruits can be harvested 8-9 weeks after sowing depending on variety. The best size of fruits is a matter of taste. If the fruits are picked when small the plants will produce a greater number, but for a large total yield wait until the fruits weigh at least 500 g. Pests and diseases are seldom big problems, but slugs and snails are fond of the fruits. The plants are relatively weed tolerant and squash is a good vegetable for the lazy weeder. The biggest problem is to figure out what to do with all that squash.
vegetable list

Cucumber: Many varieties of cucumber require much warmth and moisture. In Sweden these varieties can only be grown in heated greenhouses, but there are also some varieties of ridge cucumber that can be grown outdoors in Sweden. If you want to grow cucumbers outdoors, pick a variety that is adapted to your climate. Cucumber thrives on nutrient rich soil. The yield is between seven and ten kg per sqm. You can let the plants trail over the ground or train them up trellises. The spacing could be between 30 and 60 cm in all directions. Bury the seeds under two cm of soil. The plants will die if exposed to frost and sowing should be delayed until the daily mean temperature is at least 12^oC. If the soil is to cold the seeds will rot. I protect the plants with portable cold frames until there isn't the slightest risk of frost. Cucumber plants need to be well watered at all stages of development. In Stockholm the first cucumbers can be picked about 8-10 weeks after sowing. Everyone knows the right size of a cucumber. Cucumber is more frequently affected by pests and diseases than squash. The plants are relatively tolerant to weeds.
vegetable list

Potato: Potatoes are cheap so why should you grow them yourself. The answer is that the difference in taste and quality between organically homegrown and commercially produced is greater for potatoes than for any other crop.

Potato thrives on well fertilized and slightly acid soil. You should never lime a bed where you plan to grow potatoes. The yield is normally between six and eight kg per sqm.

Plant tubers of about the size of a hen's egg so that they are covered with six to eight cm of soil. Early varieties should be spaced 30 to 35 cm apart in all directions, slower growing and later maturing varieties need slightly more space. On 1 m wide beds rows could be 50 cm apart and the tubers 30 cm apart within rows. Although potato is a cool season crop that grows best at soil temperatures between 16 and 20 degrees C, it is sensitive to frost and cold soil. Planting too early in damp, cold soils makes it more likely that seed pieces rot. Potatoes planted early may also be frozen back to the ground by late frosts, but plants usually recover fully. The tubers can be buried as they are as soon as the daily mean temperature rises above 7-8 degrees C, but it's better to sprout them indoors. About four weeks before planting out you place the tubers on a tray in a light but not to warm place out of direct sunlight. Put the tubers in the soil very carefully to not brake the shoots when the shoots are 1 cm long. To produce many but small potatoes leave all the shoots on. For bigger but fewer tubers remove all but two or three shoots.

Water moderately, but give lots of water when flowers appear to increase yields. Harvest starts two weeks after the onset of flowering. First harvest is 8-10 weeks after planting for early varieties (if the tubers were sprouted indoors) Potato is a poisonous plant. Flowers, shoots and green or damaged tubers all contain alkaloids that may cause symptoms like vomiting, headache, diarrhoea and fewer. Green, bruised or sprouting tubers should not be eaten, but make good seeds. Green potatoes are green because they contain chlorophyll as a result of having been exposed to light. The problem can be solved by planting the tubers deeper, earthing up soil around the plants before they flower or by mulching. If you make ridges of soil between the rows when you plant this soil can later be used to cover the growing tubers.

Potato is prone to disease and pests. Some spread with the tubers and It's advisable to buy certified and disease free stock every year. Different varieties vary in resistance to pests and diseases. High resistance varieties are better for organic growing. Crop rotation is also especially important when you grow potatoes to prevent the buildup of soil bound diseases and pests. Weeds cannot harm potato plants. On the contrary, potatoes suppress weeds very efficiently.

Potato plants grow best in relatively cool soil. In climates with hot summers a mulch will slow down the warming of the soil, and prevent that the soil temperature reaches excessive levels. If the soil temperature is higher than 25 degrees C tubers may fail to form.
vegetable list

Vegetables

The vegetables