The best way to prevent disease on your plants ,is to grow
A healthy plants and choose disease resistant varieties to start with
B Biodiversity the more beneficial animals and insects visit or live in your garden or on your allotment, the bigger the chances of a balanced ecosystem.
C crop rotation and companion planting
D timing and physical barriers
A In organic , biodynamic and lunar gardening the gardener is aware that healthy soil is important and imperative to healthy plants. It is the first step to grow strong plants which are much more resistant to disease. Sometimes we as gardeners don’t have too much impact what comes our way in terms of air borne diseases and pests which could invade our gardens and plots. But strong plants are much more likely to withstand attacks by pests, fungi and other diseases.
When you choose your seeds, plants or seed potatoes look out for more resistant varieties and choose plants suitable for your local conditions.
Biodiversity is good for many reasons. Especially in organic and lunar gardening you aim for a balance. Sometimes birds can be a pest, but then they also eat lots of the “enemies” Lots of bugs are very beneficial and depend on a whole ecosystem which thrives in a healthy soil and on an organic piece of land. Normally all the different species have a role to play and it is not always clear what impact it has in the long term, if we eradicate one species which actually could feed something very beneficial .
Crop rotation and Companion planting is another useful tool to keep certain disease under control and prevent our crops from damaging pests. By rotating your crops it is less likely that diseases specific to a certain crop can establish themselves. For example club root is a serious fungal disease, attacking all brassicas. It will stay in the soil for years and the best prevention is crop rotation. It also prevents the soil of becoming depleted of certain nutritions. With companion planting you can deter certain pests by planting other crops in between .For example the smell of onions or garlic next to carrots puts the carrot fly off to lay their eggs or the smell of tomatoe leaves planted between cabbages discourages caterpillars. See our page in the booklet which comes free with the Organic gardenin calendar “In Tune with the Moon”.
You also can mulch with strong smelling plants/herbs like tansy, worm wood to keeo pests off.
Timing of sowing and physical barriers are also a good way. For example the carrot fly lays its eggs mainly in June and August. So if you sow your carrots really early you can avoid the active phase. Also when you thin out your carrots, do it as late in the day as possible as the flies get attracted by the smell. A fleece to cover your crop also comes useful . The same applies to peas, which can be attacked by moth, lying their eggs. Again plant early to avoid the active period of the moth when the peas flower or cover in the night when the moth is active.
Fruit trees can be protected by applying a barrier on the stem and in a green house adding predatory insects is common in organic gardening.There are many chemicals, fungicides and harmful products available , but most of them do not have a place on the shelve of an organic gardener or somebody who would use the lunar phases to grow vegetables and flowers. Most of them are harmful to other insects and bees and at the end of the day to the consumer (you)
You can also make you own less damaging solutions to get rid of some unwanted pests and diseases.
Anti-Fungal Preparation Horsetail Infusion (rich in Silicea)
Use 500g fresh or 50g tried Horsetail (Equisetum) and soak for 24 hours in about 3 litres of water (rainwater if possible) Bring to the boil and simmer for 15 to 20 min. Dilute up to 1:10 and spray on plants and soil underneath plants. IF fungus is present already repeat procedure on 3 consecutive days or use as preventative (potatoes, tomatoes)
Anti-Bug Preparation Tansy or Wormwood Infusion
Use 100g fresh or 10 g dried Tansy or Wormwood for 3 litres of water. Bring to boil (no soaking required) and simmer for 15 to 20 min. Dilute up to 1:10 and spray on plants.These plants are also useful as mulch .
Most common diseases
Blight (fungal disease, thrives in warm and humid conditions) effect potatoes and tomatoes.
Never plant potatoes and tomatoes next to each other. Tomatoes are best grown under a shelter (to prevent the leaves getting wet)As prevention spray horsetail solution if blight is present already spray at least 3 times on the plant and on the ground , burn affected leaves and dig up potatoes as soon as possible
Carrot-fly:prevent by sowing your carrots early.(in June and August the carrot fly lays its eggs)
Never sow carrots in soil, treated with manure.Plant next to leeks, garlic, onions or mulch with strong smelling herbs Covering the carrots with fleece also helps and thin your carrots as late in the day bas possible (the smell otherwise attracts the carrot fly)
Cabbage root fly- fit brassica collars
Mildew (fungi) in damp and humid cond.- always remove affected leaves immediately. Disourage the onset by ensuring good air circulation, avoid overwatering and spray horsetail as poreventative