Soil Types

Olive trees will  tolerate a large range of soil conditions, preferring a neutral to alkaline soil  type.. Olives will often grow in hilly, rocky areas that are not suitable for other crops.  However, they do not like very heavy soils that hold excessive water after wet periods.

It is important to understand your soil type, structure and pH prior to planting. After the trees are in the ground, there is very little you  can do to alter drainage and other essential factors. You can buy a very easy-to-use pH Test  Kit from Olive Agencies to do your basic tests.

Climate

Olive trees like cool/cold  winters and hot summers. Even though olives are evergreen trees, they still need a cool winter so they can rest to prepare for their main shooting, flowering and  fruiting in the spring

Throughout the world olives are grown in climates which range  from the cold of Tuscany (Italy) where minus 20 degrees Celsius is not unheard  of, through to warmer areas such as Seville (Spain) where some regions don't even reach 0 degrees Celsius during winter. Summer temperatures are important for the growth of fruit-bearing foliage. Most olive growing regions of the world  have average maximum daily temperatures, in the hottest month of summer,  somewhere above 30 degrees Celsius. Afternoon temperatures as high as 45 degrees Celsius have very little effect on mature olives as they have an inbuilt mechanism which temporarily shuts down their system until the cooler part of the day arrives. However, apart from the cool winter and warm summer requirements,  the moisture levels of the tree must also be adequate

Keep a good eye on the health and moisture  levels of your trees during winter to ensure that no damage occurs

The main factor affecting the spacing decision is the type of harvesting machinery to be used on the grove. Harvesters are manufactured for all densities but their availability to your grove's location must be considered.

Mainly use machine picking when you only produce olive oil, but when producing table olives, one has to go back to traditional way of picking.

There is ongoing research in every olive growing country to ascertain the best tree spacing for mechanically harvested olive groves. While there has been a tendency towards closer spacing in the last decade, harvesting economics on densities closer than 400 trees per hectare are still being  assessed.

When to Plant

It is widely accepted that olive trees can be planted in irrigated olive groves year round if the winter temperatures do not fall below minus 5 degrees Celsius. Traditional  plantings in Mediterranean countries are done in the autumn leading up to the winter rains. However, access to irrigation water reduces the need for such seasonal planting. A properly irrigated grove will withstand much greater extremes in temperatures than a traditionally planted dry land grove.

Planting an Olive Tree

Just like any tree, there's more than one way to plant an olive-

Lime

If your soil requires the addition of lime to bring it's pH level to 7.0-8.0 (neutral to alkaline), then  add the required amount to the manure and crusher dust above. Contact your local  Department of Agriculture or fertilizer company if you need pH testing done and lime quantities worked out. Many growers use a spreading contractor to apply the  lime along the total row rather than just at each individual tree site. Your own  inexpensive pH test kit will be handy for spot checks throughout the grove. More details on the use of lime for olive tree health can be found in OLIFAX 15.

Deep Ripping

Next, deep rip at least 10 to 12 furrows along the full length of the planting row to a depth of  600mm or more and a width of at least 3 metres. The nutrients will be suitably mixed in as they drop down the ripper grooves. This preparation will give the  roots an excellent start and fast growth will result. Wide shoed rippers pulled by a good sized dozer will do an excellent job. You may wish to finally level the ripped area with offset discs, a rotary hoe, blade or similar.

In poorly internally drained soils, deep ripping both along the  rows and then some cross-ripping will increase subsurface drainage. Please  consider possible erosion when planning the direction and timing of your ripping. Deep ripping during a heavy rain season may result in erosion if grass  cover cannot be quickly re-established.

After selecting the tree site, positioning your stake, and wetting the planting site, plant the tree at the same depth or just slightly deeper than it was in the pot. Do not tease the  roots out before planting as this will stress the tree by damaging the young brittle roots.

Press soil down lightly around the tree roots to remove any air pockets and make a slight depression to act as a watering basin.

Water thoroughly immediately after planting and mulch with coarse straw to conserve water, cool the soil, and reduce weed growth. The best mulches to use are those that contain plenty of nitrogen and other minerals to feed the tree. These include lucerne, soya bean and pea hay. As the mulch decomposes over a period of time, the nutrients are  transferred into the soil by earthworms, rain and micro-organisms. If using mulch, try to buy spoilt (rain damaged) bales, which are often available for  just one or two dollars each. Loosen up the 'biscuits' before applying.

Hammer milled pine wood waste can also be used but an  occasional nitrogen fertiliser application will be needed to reduce its leaching  effect. Carefully used, well rotted manures can also produce an excellent  mulch.

If you are in an area with long, cool, wet winters then mulch  may hold too much water during this period. Remember to keep your mulch about 100mm (4") away from the trunk to allow the tree to breathe and to avoid contact between the trunk and wet mulch.

Continue your irrigation according to the section on "Irrigation" and using general common sense. Be  careful not to waterlog the soil as excess water is the olive's worst enemy.  Further information can be gained by reading OLIFAX 5 on  Irrigation.

NB. All trees are 'container grown' and can be planted in  moderate climates (eg. winters that don't go below minus 5 degrees Celsius) at any time of the year. Very young trees may need some protection from severe  frost and animals. No transplanting shock will occur if the simple instructions above are followed.

Congratulations - Now watch your olives  GROW!

Growing, prunig, fertilizing & watering

Staking

The staking of young olive trees is very important. Stakes need to be strong enough to support the tree while the anchor roots are developing, and yet flexible enough to allow the tree to move freely in the wind. If the stakes are too rigid then the tree will be  over supported and not sense the need to develop strong roots and a thick trunk.

Our commercial grove sized trees are only lightly staked and will need to be tied to a heavier stake at or soon after planting out. The trained straight trunk will make fruit harvesting easier if a 'tree shaker' is to be used. The final stake should be 1500mm long and 16-20 mm thick. Two types  of stakes - coated steel and bamboo - are available from Olive Agencies.

The steel stakes are coated in a hardened, waterproof and UV stabilised polyethylene and, like bamboo, are smooth, light and flexible.  Because of their durability, they will last many years and can be used a number of times. The stakes are 1500mm long and are approximately $1.40 each plus  GST..

trellising is more expensive than the common bamboo stakes  used on traditionally pruned groves but is necessary for the development of monoconical groves. Trellises are also used in groves with densities greater  than 400-500 trees per hectare as monoconical pruning is considered the only  viable method for such intensities.

Irrigation

Olive trees need very little water to survive if serving as an ornamental or landscape tree. However, for a good crop, mature olives generally need at least two waterings to field capacity (full depth of roots - approximately one metre in mature trees), each winter (this will depend on your soil type). If more is available during winter and at other times of the year then this will be most beneficial and will result in increased crops. In fact, it is generally accepted that a drastic reduction  in rainfall and irrigation water will result in a poor crop of only one third to one half of a fully irrigated commercial crop.

It must be remembered however, that the olive's worst enemy is too much water - especially during the winter months when there is less  evaporation taking place. So keep a good eye on the moisture levels in the soil  around your trees. Winter watering keeps the trees healthy for a good spring  flowering and a good fruit set. When the fruit has set, in addition to natural  rainfall, supplementary watering is needed to achieve a good fruit size and high oil yield per hectare..

Water Quality

Every tree likes good quality water but the olive tree is still one of the few fruit bearing trees  that will survive and still bear quite well with poor quality saline (salty)  water. Saline water that is unfit for human use is generally quite suitable for  olives. Olive trees grow and crop well using water with a conductivity of up to  2,400 micro S/cm (This can be translated to Total Dissolved Ions by multiplying  by 0.64. eg 2,400 mS/cm x 0.64 = 1,536 TDI). If saltier water is used, it should  not be sprayed onto the leaves and the ground will need to be 'flushed' with good rain water from time to time. The higher the conductivity increases above  2,400 micro S/cm, the more the olive crops will begin to decrease in  tonnage.

Weed Control

Although controlling weed growth is a simple process, many growers find it to be the most time  consuming part of their young grove's management. To achieve early crops, weeds must not be allowed to grow around or near the tree, especially in the first couple of years. Weeds compete for water and nutrients, and when totally out of control, even light. Competition from weeds will slow down a young tree's growth  and may cause sickness and even death if not addressed.

Keep a 'weed free zone' from the base of the trunk to at least 300mm past where the foliage stops. As the foliage increases in diameter each year, so the diameter of the "weed free zone" will need to increase also. The  majority of the tree's roots are in this area and must not be held back by weed competition. This area can be kept free from weeds with the careful use of herbicides and/or mulches.

There are some basic pruning facts to keep in mind. Firstly, olive trees need sufficient light and air through their foliage to bear  commercial crops. Light and air through the canopy also reduces the incidence of  pests and fungal problems. The most common way of ensuring this is by pruning  the tree into a vase shape. The tree is then open in the centre thus allowing light and air penetration.

For general grove hygiene, cut any branches off that hang too  close to the ground and remove any dead branches. Also remove branches that cross over in the middle of the tree..

For logistical reasons, most large scale olive groves simply use urea and other fertilisers and trace elements to supply soil and foliage  nutrients throughout the year. Fertigation, where the fertiliser is added  through the irrigation system, is a common and economical way of supplying  nutrients.

The main fungal problem is known as Peacock Spot (Cycloconium oleaginum). This  grows on the leaves, finally causing the leaf to drop from the tree. Severe  cases can defoliate a tree leading to reduced crops and occasionally even loss  of the tree. Simple control measures include the use of copper  fungicides.

A root problem which is usually found in overwatered groves is called Verticillium Wilt (Verticillium dahliae). Research is still being done into the exact cause of this problem.  Olives can also be affected by Phytophthora and again, this is generally  encouraged by excessive soil moisture and a lack of oxygen around the  roots.

Insect Pests

These are currently fairly much restricted to the brown olive scale and olive lace bug. Insect pests will be minimal if the trees are kept in good health. At any rate, the need to spray for insects is minimal. Check with a local agricultural chemical supplier  to see which chemicals are registered in your state.

Birds

Birds do not generally favour the fruit because of its extreme bitterness before processing. However,

Production

Trees that have been planted and cared for correctly, begin to produce olives about three years after  planting and the first commercial crop arrives in year six

These yield statistics came from fully irrigated trees. In low rainfall areas where extra irrigation water is not available, the yields will be considerably less than the above figures. Good irrigation and tree maintenance practices or lack thereof, will either increase or decrease the annual yield.

Harvesting

Fruit is harvested green  (unripe), turning colour (half ripe), or black (ripe) between February and June( April and August in South Africa)  each year (This will vary according to the latitude and climate of the grove).  The fruit is then processed by yourself or sent to an oil processor, fresh fruit  market or pickling factory. The fruit can be hand picked or raked out of the trees by using a garden type rake with fairly close prongs. Olive Agencies can supply a range of harvesting tools from simple hand rakes through to pneumatic  harvesting tools and beyond. A ground sheet of nylon mesh, plastic or cloth can be used to collect the fruit.

The olives used by Drakenstein Olives are hand picked to ensure the best quality table olives. We select and process the olives ourselves on the premises.

Raking of olives are mainly done when the whole crop is used to make olive oil and where brushed olives is accepted.

Mechanical harvesting

of fruit is currently done by a range of  'tree shakers' which can be fitted with catching systems to collect the falling fruit. Mechanical harvesting methods are used with varying degrees of efficiency  depending on the machine design and the grove suitability.

Oil Extraction

Olive oil is  extracted from healthy fruit. There are two main types of  machinery used for the extraction. The traditional press is a series of mats on which layers of crushed olives are placed in a paste form. These mats are then squeezed very tightly together and the oil and water are squeezed out of the paste. The water is then separated from the oil before the oil is ready to use.  The mats are then manually cleaned and reused. Intensity of labour and hygiene  difficulties have always been encountered with the old traditional mat  system.

The most modern factories use the hygienic continuous flow oil extraction machines. These machines allow for a single person to add the olives at one end where they are then washed and crushed into a paste. The paste is then mixed to start the separation of the oil. It then goes through a centrifuge which separates the oil and water from the paste, and finally into a separator  which divides the oil from the water. The oil then comes from the machine with  very little intervention by people involved. There are a number of types of continuous flow machines which vary in the processes outlined above. This continuous flow method greatly reduces labour costs and increases production output and hygiene.

Olive oils are processed and sold in many different grades. Oil  is marketed in bottles, pressure packs or cans. Herbs or even olive twigs with  leaves can be added to the bottles for that 'something different' gift. Olive  oil is also used in margarines and other mainstream foodstuffs.

Olive oil soaps are produced as blocks or in liquid soap and powder form. Soaps and oils can also have different scents added to them to  appeal to all 'tastes'. The Japanese are using olive oil in a wide range of cosmetics, shampoos, conditioners and health products.

Green and black olive paste can be marketed for use as a spread  on bread or for adding to salad dressings. Olive dips are produced for use with  biscuits or other snack foods. Many souvenirs in olive growing countries are made from olive seeds and olive wood. Olive groves are also developed as tourist  attractions, complete with retail stores, cafes, chapels and processing facilities.

Olive Leaf Extract is proven to be anti-bacterial, anti-viral and anti-fungal.

Olive by-products such as waste cake and olive seeds are being used to produce everything from electricity to fertilizers, stock feeds,  activated carbon, bricks and even plastics.

Due to continually rising demand, it appears that the number of  commodities and methods for the marketing of olive products is limited only by human imagination.

The following written text is from the “Oliveaustralia” website. (Peter Fuller, The Australian Farm Journal)