Yellow leaves – potted citrus


A reader wanted to know what what is causing yellowing of new leaves in her potted, dwarf lemon tree. From the photos she e-mailed, it does look like this tree has an iron deficiency, as yellowing is showing in the young leaves. This can be caused by a number of conditions:

a) potting mix (or soil) that is too alkaline from excess bio-char or calcium in the mix or fertiliser containing a lot of poultry manure
b) cold and wet soil or growing mix
c) if there is a build up of fertiliser salts from synthetic fertilisers, or
d) where there is an excess of potassium from synthetic fertilisers or over-use of seaweed liquid fertiliser.

The first thing to do is check that your pot has ample drainage. Large pots should not sit directly on a hard surface. While smaller pots usually have ample drainage holes around the sides at the base of the pots, large pots often have only one large hole in the base and this can easily become blocked resulting in poor aeration and/or a concentration of fertiliser salts if synthetic fertilisers have been used. Large pots should have pieces of tile placed under the pot to allow a small space between the base of the pot and the verandah or paving. If you notice crusting around the top of the soil line (fertiliser salts), flush the plant with clean water, once drainage has been improved.

The next step is to check the pH of the mix with a test kit. A suitable pH is important to all parts of your garden as the pH in soil or mix controls the availability of nutrients. Test kits are very economical to use and readily available from larger nurseries. If you find that the pH is above 7.2, you could repot the tree using an organic-registered potting mix as organic matter is an important source of iron. However, to do so may result in the loss of this crop of fruit.
The addition of flowers of sulphur (elemental sulphur) is the usual way to reduce pH in soils, but it is easy to overdo this in potted plants. You can apply iron chelates (the form of iron in organic compost) to the mix in the pot at the recommended rate. Citrus trees do not absorb iron chelates well through foliar spraying. Or, you can fertilise the tree with a weak solution of Multicrop’s Ecofish. This is an organic-registered liquid fertiliser that contains soluble iron and has a low pH, qhich will help to reduce the pH in the pot. Ecofish contains iron, manganese, sulphur and zinc (trace elements needed by citrus). Manganese deficiency is also caused by high pH or poorly-drained soil.

Rust diseases

There are hundreds of types of fungi that cause ‘rust’ on plants but each type has a limited number of host plants so that your whole garden is not likely to be overrun by rust.
Rust can occur in various seasons but it does need moisture to grow. It typically causes yellow or brown markings on upper surface of leaves, and small yellow or brown powdery growths on the underside of leaves. The powdery substance consists of fungal spores that can be blown about by wind, infecting other plants that are susceptible to that type of rust fungus.
Below, on the left, are pictures of rust on the underside if a frangipani leaf and typical signs of rust on grasses. Some leaf markings can be confused with fungal diseases. On the right are pictures of hail damage on a cycad and spores on the underside of a fern frond – which is how ferns reproduce.

Basically, rust diseases are a sign of malnutrition that produces an unsuitable pH on the leaf surface. Plants, like humans and animals, are more prone to diseases when they have a poor diet, and rust diseases can be avoided by keeping plants growing vigorously – but this is not always possible in extreme weather conditions. Sulphur or copper are the usual treatments for rust. Both of these are nutritional elements that can be supplied by various fertilisers, including seaweed extracts. Seaweed also contains plenty of potassium that strengthens cell walls, sulphur, and trace elements (including copper) that boost plants’ immune systems.
For mild cases of rust, remove damaged parts of the affected plant and burn these, or dispose of them in a sealed plastic bag. Don’t ever compost them, as the spores may not be killed. Then give the plant a foliar feed of seaweed extract tea and water some into the ground over the root area. Improve your fertilising program using a complete organic fertiliser.
For deciduous plants, rake up and dispose of dropped leaves to avoid reinfecting the plant. Apply the seaweed tea at bud swell.
For more severe cases, after removing damaged foliage, plants can be dusted with elemental sulphur (flowers of sulphur. However, as the spores are under leaves and the dust can be difficult to apply, affected plants can be sprayed with wettable sulphur in cool weather only, as sulphur will damage plants when temperatures are over 24 degrees Celcius. Be aware too, that sulphur will also kill pest predators. If these are present on affected plants, apply chamomile tea (one tea bag to 500 ml water) instead.

Traditional Moon Planting

All about traditional moon planting

Traditional Moon Planting is an ancient agricultural practice that has been used by farmers for several thousand years and is still practiced today. It is based on the synodic period of the Moon from one New Moon to the next, an average period of 29.5 days.
Over time, farmers observed that all aspects of farming were affected by the interaction of the gravitational forces between the Sun, the Moon and Earth. These are the same gravitational forces that affect ocean tides around the world. Because the Moon is closer to Earth, its effects are more noticeable. These observations were handed down to younger generations as their community’s survival depended on getting the best results from their crops.
Scientists have more recently confirmed that variations in sap flow, biological functions in plants, and subtle changes in Earth’s electro-magnetic fields, correspond to the Moon’s gravitational pull. Scientists have also confirmed that the Moon has an influence on breeding and feeding cycles of many life forms on this planet. As plants contain a high proportion of water, it is not surprising that they would also respond to a force that can move huge bodies of water. And, when you consider that plants absorb nutrients as ions that carry either a positive or negative electric charge, you can see how changes in electro-magnetic fields can affect the growth of plants.
The Lunation Cycle
Each lunation cycle the Moon passes through four phases – New Moon, First Quarter, Full Moon and Last Quarter. The number of days between each change of phase can vary from 6 3/4 to 8, so to make it easier for you, the current moon phase and its duration can be found by clicking on the ‘Current moon phase’ icon in the menu bar.
The Waxing Moon
During New Moon and First Quarter phases, the Moon is increasing in light. In these two phases, sap flow increases in the above ground parts of plants, and these are the most suitable phases for sowing and transplanting annuals (and biennials). Flowering annuals, grains, melons and spring onions do well if planted in either phase but, generally, New Moon phase is best for leafy annuals and First Quarter is best for fruiting annuals. Liquid fertilisers will take effect more quickly if applied during the waxing phases. Shrubs and trees can be pruned in First Quarter phase when you want to produce new growth quickly, such as pruning spring-flowering shrubs or summer pruning of roses. When pruned while sap flow is high, sap is quickly diverted to the lateral shoots. When sap flow is low, regrowth is slower and dieback is more likely to occur in some plants. First Quarter phase is also good for grafting and budding because these require a high sap flow for successful results.
The Waning Moon
During the Full Moon and Last Quarter phases the Moon decreases in light and sap flow in plants is more concentrated in the root area. As sap flow gradually slows during these two phases, Full Moon phase is best for sowing and planting because germination is lower, and regrowth slower, during Last Quarter phase. Because sap flow is lower in the foliage part of plants, crops or seed harvested for storage or drying are less likely to rot if harvested during the Moon’s waning period.
Full Moon phase is best for the sowing and planting of both root crops and perennials (plants that live longer than two years). All trees, shrubs, vines (including fruit trees and vines), globe artichokes, asparagus, rhubarb, strawberries, herbaceous perennials, bulbs and lawn grasses are perennials. The reason that these plants are planted (or sown) in the root vegetable phase is that perennials have a different type of root system from leafy and flowering annuals. Roots of perennial plants have, like root vegetables, the ability to store carbohydrates and nutrients, and this type of root system is important for the longevity of perennials.
Because Full Moon phase favours root growth, this is also an excellent phase for taking cuttings, or for aerial layering, because root growth must form to support new foliage growth. This is also the best phase for dividing plants for the same reason. Prune dormant plants during Full Moon phase. Last Quarter phase is best for cutting back rampant shrubs and vines, – regrowth will be less vigorous.
Fertile and Barren signs
Traditional moon planting uses the tropical zodiac that divides the celestial belt into twelve equal parts of 30 degrees, named after the constellations that were closest to them in the second century B.C., and ignores that fact that the actual constellations vary widely in size. The twelve segments were also given labels of ‘positive’ or ‘negative’. The equal divisions were basically markers for degrees of tension from the major permanent points of reference (the Solstices and the Equinoxes), which occur within 24 hours of the same days each year.
Negative segments are considered ‘fertile’ and the best days within a phase for sowing, planting, taking cuttings, budding and pruning to encourage growth. Positive segments are considered ‘barren’ and best days within a phase for collecting seeds, harvesting crops and for storage and weeding.

Does traditional moon planting work?

As someone who has obtained certificates in both astrology and horticulture and had been working in horticulture for some 40 years, I felt competent to test and assess the various moon planting and gardening guides available to the public. Over a period of eight years, I experimented with and compared different forms of moon planting against detailed records of sowing, germination, growth, harvesting and pruning.
Some moon or lunar calendars and guides advised readers to plant all plants that produce fruit above ground during First Quarter phase. This ignores the different root system of perennials. Other guides totally ignored moon phases and focused on the astrological signs. The tray below on the left was sown during Full Moon phase, which is an incorrect moon sowing phase for leafy annuals. The tray on the right was sown two weeks later during New Moon phase. Both were sown in the same seedling mix and received the same amount of care.

I found that most moon planting guides in women’s magazines are prepared by astrologers who have used the astrological ‘rulership’ of plants rather than moon planting methods that have been handed down through the centuries. These interpretations have produced some results that make no horticultural sense and must be confusing for readers.
The designation, by traditional moon planting farmers, of fertile and barren ‘signs’ varies slightly from the fertile/negative and barren/positive labels applied in astrology, and I feel there had to be a reason for this variation to remain constant through the centuries. Although there has been no scientific study into this part of moon planting, I believe it relates to the changes in the Earth’s electro-magnetic field and the absorption of plant nutrients, which must be absorbed as water-soluble electrically-charged ions.
Some moon or lunar planting guides will tell you to avoid watering your garden on ‘fertile’ days while others will advise to avoid watering on ‘barren’ days. A perusal of rainfall records will show that Nature doesn’t follow these rules. Gardens should be watered when they need it.
After comparing the various methods of Moon Planting, I came to the conclusion that the traditional moon planting method, although the simplest to follow, made the most horticultural sense, and it works best for us. The basic rules, or principles, are described below.

Traditional moon planting ‘rules’

1. Avoid sowing, planting or taking cuttings from 12 hours before to 12 hours after the exact change of moon phase.
The twelve hours immediately before and after the exact change of each phase is not a good time for sowing, planting, or taking cuttings. We have found that the increase or decrease of unfavourable energy is gradual and it will not have an obvious effect if you run an hour or so into this period when you have a lot of sowing or planting to do. While this is not a good period for sowing or planting, this time can be used to prepare beds or compost heaps, apply mulch, etc.
2. NEW MOON PHASEthe best time to sow or transplant leafy annuals (we eat the leaf or stem), and flowering annuals. Also sow annual grasses, green manures, and apply liquid fertilisers. Mow lawns to encourage growth. This is the second best phase to sow or transplant fruiting annuals.
3. FIRST QUARTER PHASEthe best time to sow or transplant fruiting and flowering annuals (we eat the fruit or seed bearing part), and grains. Also sow annual grasses, green manures, and apply liquid fertilisers. Prune to encourage growth and deadhead roses and flowering annuals. Carry out grafting and budding. Mow lawns to encourage growth. This is the second best phase to sow or transplant leafy annuals (we eat the leaf or stem).
4. FULL MOON PHASEthe best time to sow or plant out root crops and all fruiting and decorative perennials, including fruit trees. Also sow lawns or lay turf, harvest for storage, take cuttings, divide plants, prune dormant plants and apply solid fertilisers. Mow lawns to slow growth.
5. LAST QUARTER PHASE – no sowing or planting during this phase. This is a good phase for attending to your soil; weeding, applying mulch, making compost, preparing manure teas, applying solid fertilisers and digging or ploughing, if necessary. Prune to restrain growth, and mow lawns to slow growth during this phase.

A current, colour-coded, easy-to follow traditional moon planting and gardening calendar is available for purchase HERE.