Examples of sustainable fertilization for some vegetable plants

Garlic

Aubergine

Beetroot

Cardoon

Prefers humus-rich silico-clay soil. Excessive limestone hardens the cardoon. Requires potassium to be introduced at the beginning of the crop (organic or mineral). Nitrogen is then added in the form of urea pearl 3 times during the growing season. Dose 0,200 Kg/are.

This vegetable plant of Mediterranean origin is less sensitive to seed set if sowing is done in early spring after the last frosts. Its growth slows down in the hot season and becomes more vigorous at the end of the summer.

Carrot

Too much nitrogen increases the production of split roots. Carrots are sensitive to potassium, but too much quickly produces an induced magnesium deficiency. A brown colour of the roots indicates a boron deficiency. Too much straw manure results in forked roots.

Celery root and celeriac

For some varieties, it is excess sulphur that causes leaf chlorosis. A soil laboratory analysis is the only way to know the origin of this disease. If there is a magnesium deficiency, this can be corrected by spraying with a 1 to 1.5% solution of magnesium sulphate (this product is also known in sports circles for its muscle-relaxing properties), which can be purchased from websites, agricultural COPs and some garden centres.

An effective product is “Algoflash anti-browning conifer care” (conifers are also very sensitive to magnesium deficiency). Some growers use this solution every year as a preventive measure. It is also possible to incorporate a bottom dressing before planting, such as Binore blue fertilizer, which contains magnesium.

Leaf chlorosis can be confused with early wilting caused by a heatwave. Celery will produce new leaves as soon as the heatwave is over, provided it is well watered. Head size will often be smaller.

Fractional applications of non-calcium-bearing nitrogen (such as potassium nitrate) before root balling (celery head formation) increase yields. The total dose is about 0.130 kg/are divided in 2 times. After head formation, nitrogen has an adverse effect. If too much nitrogen is used, rust-coloured spots appear on the roots. Potassium chloride (2 kg/are), when available, would also give good results.

Celery is very sensitive to boron deficiency, which is not easy to manage (it manifests itself mainly in reduced growth). The level of boron deficiency in the soil must be determined before cultivation by a laboratory analysis, as excess boron is also toxic. Boron deficiency during the crop cycle can be corrected with foliar fertiliser. Binore blue fertiliser, which contains boron, is very suitable for this type of crop.

Cucumber

Molybdenum can be supplied in a complete liquid fertiliser for pot plants or garden plants (including several trace elements; available in garden centres and on the Internet, e.g. by clicking here) or in a liquid fertiliser including boron, available from agricultural suppliers or on the Internet. Molybdenum should be applied systematically in cucumber crops as a preventive measure.

Cucumbers require a lot of fertiliser if they are to produce fruit for 4-6 months, so regular nitrogen applications are needed every two weeks (e.g. Binor sulphonitrate, potash or lime nitrate, soluble calcium nitrate), i.e. about ten applications during the growing season. Approximate dose of nitrogen for each application: 0.100 to 0.150 kg/are. Potassium and phosphorus applied as a bottom dressing before planting should be sufficient. A high potassium application does not improve yields.

Courgette

Shallots and other edible onions

Shallots should be harvested in July before they are completely wilted and after checking the condition of the bulbs. If one waits too long, mould will set in the bulbs.

The shallots are placed on a rack in the open air, protected from moisture and sunlight, until the foliage is completely wilted. The tops are then collected and placed in a compost bin. In this way, any risk of soil-borne diseases is greatly reduced, and the shallots will be well nourished in a soil that is still well supplied with humus from previous years and maintained by rotation. This cultivation technique should be adopted for all consumable bulbs such as Mulhouse onions

Bean

Apart from the fact that it is susceptible to viruses brought by aphids, the bean is known for the peculiarity of its roots where nodosities shelter nitrogen fixing bacteria. However, a nitrogen deficiency can occur at the beginning of a spring semi, as the soil is not sufficiently warmed up for the nitrogen fixing bacteria to develop in the nodules. Beans are very sensitive to zinc deficiency. It is sensitive to copper and molybdenum deficiency. It does not like calcareous soils prone to manganese deficiency. All these deficiencies can be avoided by adding well-decomposed compost before planting and by not planting during the cold season. Potassium is a determining element in bean cultivation. Unless the soil is already well supplied with potassium, it must be added during the crop, e.g. in the form of potassium nitrate.

Lettuce

To avoid this inconvenience, it is necessary to adopt the cultivation method used by market gardeners, which is to renew the plantations every week. For the summer season, heat-resistant varieties such as lazy blond lettuce should be chosen. The harvest period lasts only a few days for each planting. A home gardener must calculate his consumption of lettuce over a week in order to plan the number of plants, taking into account possible losses due to slug attacks, botrytis, hail, etc. The periodic renewal of plants allows for production until the frosts. It should be noted that in large-scale market gardening, lettuces are often transplanted onto a plastic cover to reduce weed growth. This process avoids mechanical or chemical weeding, and saves time and money for the market gardener.

Melon

Melons are grown on particularly well aerated soil in order to obtain deep roots. A very deep ploughing is even recommended, of the order of 40 to 50 cm or more. It is a plant that needs frequent watering and is very sensitive to iron, magnesium and molybdenum deficiency. It is also sensitive to phosphorus deficiency, resulting in a drop in production of around 50%. For this reason, some vegetable growers apply soluble phosphate during the crop cycle. Poor nitrogen supply results in flower drop and loss of production. An excess of nitrogen also produces a loss of yield.

In the Provence-Alpes-Côte-d’Azur region, open field cultivation by market gardeners and farmers is noted in the spring by the use of plastic tunnels and plastic mulches. This technique has the disadvantage of reducing the possibility of making additional nutrient inputs. For this reason, and also because it is very suitable for melon cultivation, fertilisation is mainly carried out before planting. Several studies have shown that a large amount of compost before planting is very favourable to the melon crop, provided that the compost is ploughed in 4 to 6 months before planting to avoid the transmission of telluric diseases. A good result can also be obtained with a mineral fertilizer applied in the spring before planting. In the middle of the crop cycle, a small dose of nitrogen is useful, the dose being 0.060 to 100 kg/are.

Turnip

Parsley

Leek

Leek cultivation is fairly easy provided that the soil is rich in nitrogen, phosphorus and potassium, in the order of 1.5 kg/are to 0.6 kg/are for these two major elements. If the soil is sufficiently rich in potassium and phosphorus, 60% of the nitrogen (urea or ammonium nitrate) is supplied in 2 to 4 applications after transplanting. Total dose: about 0.250 kg/are.

Pear

Also known as chard, pear is fairly easy to grow and is not very sensitive to deficiencies in iron, magnesium, etc. However, it consumes a lot of nitrogen and especially potassium. An application of potassium nitrate during the summer season is often very beneficial. As long as the soil is well supplied with potassium and phosphorus following an organic and mineral fertiliser, only the nitrogen is applied in 3 times every 2 weeks over a period extending until the first frosts in autumn. Approximately 0.3 kg/are.

Pea

It has a fairly short vegetative cycle and is heat averse. Like the bean, its roots have nodules filled with bacteria that fix nitrogen. In case of deficiency, and although peas are not very demanding in terms of phosphorus, the latter is applied before sowing. In general, peas do not require much iron and magnesium. A soil that is well supplied with potassium and phosphorus following a compost application in the autumn does not need any additional application of these elements during the pea crop cycle.

Pepper

Potatoes

The dry climate of the Provence-Alpes-Côte d’Azur region is favourable to the cultivation of potatoes, which fear excess humidity favouring mildew attacks. It is easier in the Provence-Alpes-Côte d’Azur region to control the amount of water by irrigation just necessary to avoid mildew. Even in the Provence-Alpes-Côte d’Azur region, potatoes can fall victim to late blight caused by poorly controlled irrigation on heavy, compact soils.

Potatoes like a light and especially sandy soil; ideal conditions that can be found in particular on the island of Noirmoutier, renowned for the early cultivation of the “bonnotte”, picked by hand before maturity (90 days after planting). In this Breton island, the varieties “Sirtima”, “Iodéa” and “Lady Christ” are also grown. In order to obtain a taste quality comparable to the various potato varieties cultivated in Noirmoutier, the structure of a heavy soil must be improved by the addition of amendments rich in sand, but not only. The soil must be well supplied with humus, ensuring a good reserve of assimilable phosphorus and rich in trace elements.

Potatoes are very demanding in terms of phosphorus, which must be applied before planting or ridging; for example, solabiol rock phosphate containing 29% phosphoric anhydride for shrubs and vegetables if the reserve of assimilable phosphorus in the soil is not sufficient. An application of sulphate of potash improves the resistance of the plant, which will produce larger and more abundant tubers. All tuber varieties are sensitive to iron, zinc and manganese deficiency and very sensitive to boron deficiency. Deficiencies of these trace elements are often the cause of poor yields and diseases that are exacerbated by lack of rotation. A good quantity of compost introduced in the autumn would reduce rhizoctonia attacks.

In conventional field crops, the inputs are about 100 units of nitrogen, 150 units of phosphate and 150 units of potash just before planting in the form of 11-15-15, i.e. 10 qx/ha. At the beginning of the crop, ammoniacal nitrogen applications such as urea are very suitable. The dose is about 0.150 kg/are. If nitrogen is essential to ensure tuber growth, an excess of nitrogen favours the development of vegetation to the detriment of tuberisation. An excess of nitrogen also produces an increase in reducing sugars in the tubers, resulting in browning when fried. It is therefore necessary to carry out a nitratest before deciding on a nitrogen application.

The tubers are placed in a furrow that is ploughed with a hoe or a tool with a ploughshare to a depth of 3 to 5 cm (in large-scale cultivation a planter is used). Each furrow is then covered by a light ridging so that the tubers are at a depth of 12 to 15 cm. One to two ridging operations are necessary during the growing season. The last ridging is done at the latest when the vegetation reaches 15 to 20 cm in height.

Radish

Tomato

Phase 1: From planting to the setting of the first fruits, tomatoes consume few nutrients. This is also the period of root formation. A supply of soluble phosphorus (in the form of foliar fertiliser) produces well-filled roots. Tomato stems are fragile because they contain little dry matter. Their cuticle is fragile, which can favour the first attacks of bioaggressors. For this reason, some growers spray the plants with Bordeaux mixture as a preventive measure before transferring them to the field.

Phase 2: This lasts 9 weeks and corresponds to the formation and harvesting of 80% of the fruit, with the consumption of a lot of nitrogen and phosphorus. A large part of this phosphorus is found in the fruit. The consumption of potassium is very high. Calcium and magnesium uptake is low.

The concentration of nitrogenous matter is high in the first fruits and then gradually decreases. Foliage with light green shades indicates a nitrogen deficiency.

Tomatoes respond well to sulphur applications. Successive applications of Binor sulphonitrate and potassium nitrate are very useful.

During this phase, the stems of the tomatoes become stronger and more resistant, starting with the oldest stems; a development that can be seen when pruning the suckers when they have become too large. Total nitrogen dose: about 0.150 kg/are.

Phase 3: This phase, which lasts about 5 weeks, is characterised by an increase in the consumption of nitrogen, magnesium and calcium and a reduction in the consumption of potassium. The stems continue to grow stronger. Ammoniacal nitrogen applications are useful. Nitrogen dose, about 0.200 kg/are.

Phase 4: The plant is exhausted and enters its “third age” with a decrease in fruit production. In the open field, fungal diseases begin to set in. Nitrogen consumption is practically zero. On the other hand, calcium consumption is very high. Phosphorus consumption is normal, but potassium and magnesium consumption is very low.

fund fertilizer: Because of the high consumption of phosphorus and potassium during certain periods of the vegetative cycle, a mineral fertiliser rich in these elements complements the compost applied in the autumn in spring.