Term 1 – Week 6 – Disease, Summer Fruit & Propagation

This week we moved on from pests to diseases. Diseases in horticulture are broken down into 3 categories; fungi, bacteria and viruses. In vineyards common diseases are powdery mildew and botrytis.

Just like in humans and animals, preventing disease is obviously a much better idea than trying to cure it. Possible control methods include:

  • Growing disease resistant varieties
  • Increasing airflow around fruit
  • Irrigate under plants (wet and humidity spread disease)
  • Bring in sheep over winter to clear up any rotten/mummified fruit or leaves
  • Spray fungicides from start of first growth (vineyards spray sulfur every 10 days during the growing season)

Disease can also be spread by insects. The damage they do to the fruit can create entry points for disease to get into the plant.

Plants with diseases mainly need to be either removed totally or pruned back to healthy wood.


Powdery mildew

On Wednesday we discussed Summer fruit, basically “stonefruit” has been re-branded as “Summer Fruit”, so it’s cherries, apricots, peaches, nectarines and plums. They all belong to the same genus, Prunus. 

To ripen summer fruit you need at least 800 growing degree days a year. GDDs are added up from 1st Oct – 30 April, average temperature each day minus 10 degrees. So if the daily average temperature was 20 ºC, 10 would be added to the GDD total.

The amount of sun will effect the size, colour and flavour of the fruit.

Summer fruit varieties also need enough cold over winter to break dormancy in spring. For example, apricots need at least 1000 hours of chilling (under 7ºC) over winter. This keeps the trees dormant through winter, even if the temperature warms up slightly for a short time. Once they have had their 1000 hours they will start flowering all at once in spring, which is important so all the trees in the orchard are at the same stage at the same time.

Dry conditions are also good for summer fruit. It helps to reduce diseases like brown rot and bacterial blast.

In the afternoon we went out to the cherry trees we planted last winter and did some tree training. This just involves pruning off any unwanted branches and clipping up the rest to the wire to ensure upright growth.

In propagation class we packed up the seed from last week that had been processed and was now finished drying.


We also sowed some Sophora microphylla seeds (kowhai). They need to be scarified before being planted because they have a thick, hard seed coat. Scarification involves damaging the seed coat so they can absorb moisture and start all the chemical processes involved in germination. We used sand paper to rough up one little spot on each seed, only a little bit is needed otherwise you could end up damaging the embryo as well as the seed coat. To check if you have done enough you can soak them in water for a few hours and see if they puff up a bit.


The kowhai seed we used is from a really old kowhai tree at Northburn. It seems to flower earlier than other kowhai so it would cool if these seedlings end up taking after its parent. I think kowhai take about 7 years to flower from seed so it will be a bit of a wait to find out.

Last week’s weather:

The evapotranspiration numbers have really dropped now, so not much irrigation is needed at this stage.



Term 1 – Week 5 – Pests, Viticulture & Roxburgh


This week we started a new topic looking at pests, diseases and disorders that can be problems in horticulture and viticulture.

Pests include: aphids, codling moth, mealy bugs, phylloxera, mites, leaf-roller caterpillars
Diseases: botrytis, powdery mildew, black spot, leaf blight, rots, blast
Disorders: climate issues (hail, wind, frost), nutrient deficiencies, poor management (herbicide damage)


Codling moth damage (caterpillar stage)

Orchards and vineyards need to have plans in place to check for and to manage pests and diseases. Wayne’s advice is “what you don’t see you will get”. So if you’re not checking for something properly (and therefore not controlling) it will likely get out of control and run riot through your orchard. Wayne also pointed out that if we spotted any really fast moving insects, these are probably predators and beneficial insects.


Orcharding legend, Wayne, with a Light-brown apple moth trap

Jackson’s Orchard have traps for certain types of insects to monitor their numbers. They attract the bugs with a pheromone. One trap is for the Oriental fruit moth. Luckily that has not been found in New Zealand yet. If it is found it would basically shut down fruit exports from Central Otago.


Powdery mildew on apple leaves


Grape vine leaves infected with a virus

On Wednesday we were out at the Bannockburn Rd vineyard checking how ripe the pinot noir grapes are. We collected a few bunches of grapes at random throughout the vineyard, smushed them up and tested how much sugar was in the juice with a refractometer. Sugar levels are measured in brix. Pinot noir should be about 23 – 24 brix at harvest. If they are being used for bubbles it can be less. Our grapes will need another few weeks. Hopefully we don’t get a bad frost before then!


Testing grape sugar levels

After testing the sugar levels we went out and did some green thinning. This means cutting off the grape bunches that are still green and won’t ripen in time.


Left: nearly ripe grapes on the vine. Right: discarded grapes


Bird damage despite the nets. 

I ate some of the nearly ripe grapes and they are pretty sweet already (not as many as the birds, promise!).


Bring on harvest!

On Thursday we started processing the seed that has been collected. This meant a lot of work with a sieve! Then drying and storing the seed.


Eucalyptus seed pods


Eucalyptus seed


Muehlenbeckia astonii (wiggy-wig) fruit with black seeds

I was quite taken with the wiggy-wig fruit and seeds that looked like little white flowers.

On Friday we headed off to Roxburgh on a field trip. There’s a huge blueberry grower there that we stopped to see (15 hectares). That was really interesting, I didn’t know much about blueberries before other than that they need an acid PH soil. They add wood chip as a type of mulch to bring down the level to below 5.5.


Blueberry bushes – high bush variety

The main issues they have are pollination at flowering and weeding. Blueberries need a lot of help pollinating. They bring in 90 hives of honeybees and as many bumblebee hives as they can get. To get the ideal size blueberry each flower needs 6 visits from a bee. Unfortunately blueberry flowers aren’t bees favourite, so that might not happen especially if there are more interesting options for the bees!


A few berries left after harvest

As far as weeding goes, they do use some sprays, but mainly it’s done by hand. Over the winter they employ 3 people full time just to weed. They indicated it would be quite easy for them to go organic here in Central Otago but their parent company  is concerned that doing that would devalue their blueberry orchard in Hawke’s Bay as they wouldn’t be able to go organic.



Next we went to the massive apple packhouse in Roxburgh. It’s a pretty high tech operation just to process apples!



The machine takes 18 photos of each apple (at super speed, this conveyor belt is moving fast) and shoot it out down the slot with all the size and colour apples to be packed. These ones that are being nicely packed and arranged are going to be exported.


Signage in the packhouse

Local market, however, isn’t quite as flash:


Although, local market product doesn’t need all the sprays (pesticides, fungicides etc) that the export product does. Apparently Asian countries don’t care what sprays have been used but one hitchhiking insect can mean a whole shipment is rejected, whereas Europe is more concerned about the chemicals.


Fog along Lake Dunstan from Clyde to Cromwell

Temperatures have dropped and trees are on the turn. We’ve had some really clear sunny days that have warmed up in the afternoon, but it has been quite chilly in the mornings now.

Last week’s weather:


Term 1 – Week 4 – Plant ID & Seed collection


Sunset over Alexandra

The weather is definitely starting to turn to autumn. We’ve had a few colder days and nights and deciduous plants are starting to yellow.

This week we continued adding to our plant knowledge and got on with our plant collections. I’ve got all ten plants I need for my specimen book and they are in the press drying out.


Plants for specimen book

Here’s an example from the specimen collection:

Common Name: Irish strawberry tree
Botanical Name: Arbutus unedo
Family: Ericaceae

Cultural requirements: Full sun, sheltered, well drained soil, neutral PH

Plant description:
Tree or large shrub
Simple leaves, dark green and glossy
Leaf shape is lanceolate with a serrated margin
Inflorescence is a compound panicle, white flowers, flowers in autumn

Identifying features: Red coloured fruit, similar to strawberries. Bell shaped strawberries. Bushy.

Landscaping using / amenity uses: In dry gardens, use fruit in jam or baking, specimen tree


Arbutus unedo – Irish strawberry tree

We have started a new topic in propagation – seed collection. We went out to Bendigo and collected several different types of seeds; eucalyptus, flax, kanuka.

You can collect seed from nearly all plants. Some easy ones to collect that self pollinate are lettuces, beans, peas, herbs and heirloom tomatoes. You just need to make sure they aren’t an F1 hybrid or you will probably end up with some strange genetic variations.

Phormium tenax (flax) seed pod

Last week’s weather:


Term 1 – Week 3 – Tractors & Quads

The majority of this week was spent gaining skills on the tractors and quad bikes.


Claas tractor – the biggest tractor at Bannockburn Rd campus



First time driving the John Deere



On to the next level of tractor

Now I’ve driven all three of the tractors at the Bannockburn campus. The easiest one is the little John Deere. It’s very simple and intuitive. The next step is to get better at using the bucket and then towing implements, such as a sprayer or mower.


Ryu mastering the quad bike

Riding the quads was a lot of fun once I got the hang of them. We went out to the motor track and had a great afternoon racing around. The quads have a roll bar installed to add some protection, otherwise they can be pretty dangerous.


Weather – Hot and sunny! We’ve had a last little bit of summer before autumn hits.


Does this tree really think it’s already autumn?! Taken at Lake Hayes

Last week’s weather:


Term 1 – Week 2 – Plant Naming & ID


Dry garden in Cromwell

I’ve really enjoyed this week! I feel like I’ve learnt a lot. We started the week by learning about plant botanical names. How to correctly format them and what they mean. They need to be formatted in a very specific way. An extra quote mark or missing full stop and it’s wrong.

Knowing the botanical name makes it easier to communicate the exact plant you are talking about. Also, if you are not familar with a certain plant, the botanical name can give you clues about it, such as:

Colour: rosea = rose coloured
Geographical: nipponica = Japan
Type of flower: grandiflora = large flowered
Scent: fragrantissima = most fragant

Plant names are binomial; made up of a genus name and a species name. Example: the genus of lavender (common name) is Lavandula and should be italicized or underlined. A particular species of lavender is Lavandula angustifolia. 

Plant names can also include extra information, like if it is a hybrid:

Lavandula x intermedia – the ‘x’ denotes that this is an interspecific hybrid (species)

Or a cultivar:

Lavandula angustifolia ‘Imperial Gem’

There are lots of other variations to the nomenclature as well.

On Tuesday, with our new grasp on botanical names, we headed out into Cromwell to identify plants. We will be tested on 40 plants and need to know the botanical name, common name, identifying features and uses. We also need to make a specimen book of 10 plants. This was actually a really fun day. I don’t think many of the botanical names have sunk in yet but I’m working on it!

There was also a lecture on plant uses in landscape. It was really interesting and great gardens as examples; it’s amazing what some clever people can do with plants! Some of the points discussed were:

Design – creating unity in a space, linking certain features giving a visual connection, drawing your eye to a certain spot (enframement), camouflage

Environmental – air quality and dust interception, shelter and shade, reduction of noise and habitat creation for wildlife

Engineering – soil moisture and erosion, roots binding soil

Aesthetic – feature trees, accent planting, topiary

There is a lot to consider!


Otago Polytech roadside stall

On Wednesday we got our first look at the new orchard the Polytech has leased. It’s just before the Kawarau Gorge heading out of Cromwell. The orchard has a bit of everything. Peaches, nectarines, apples, pears, boysenberries, raspberries, cherries, plums, greengages, apricots.


Huge boysenberry!

We had a good look around and sampled a lot of the produce. Yum! One thing I really liked that I hadn’t tried before was a peach variety called Coconut Ice.


Peach picking

Then we got to work picking greengages and peaches.


Ute full of greengages

We packed them up straight away and got them out onto the stall for sale. We also got to take as much home as we wanted which was great! I’ll start looking like a peach if I’m not careful.


Freshly picked and ready to sell

Thursday was the first propagation class of the year. New students did a bit of an orientation while us oldies got stuck into some cuttings. I did semi-hardwood cuttings of Heliohebe hulkeana  (New Zealand lilac). It’s an evergreen shrub that flowers from mid-spring until summer. It has small light pink flowers; quite pretty.

The cuttings were dipped in rooting hormone and then sowed into a hygiene tray with 30% potting mix and 70% pumice. This mix makes sure there is good drainage and aeration. Then I popped it on the heat bed in greenhouse 1 and gave it a good misting with water. Hopefully I will get a good strike rate!


Heliohebe hulkeana cuttings on the heat bed. Lusi in the background.

The weather has redeemed itself this week; summer has decided to make an appearance! It has been hot and sunny everyday. Everything is staring to get really dry again.

Last week’s weather:


Term 1 – Week 1 – Back to School


The new school year has begun! There was an orientation for all students on Monday. It was great to meet the new horticulture students. Everyone has such different backgrounds and I find it fascinating how we have all ended up wanting to give horticulture a try. There are only about 7 newbies, so it will be a nice small class this year.

On Wednesday we had a day on health and safety. While important, it is not the most interesting topic. Although on the positive side it seems that whenever Wayne takes a class I always end up feeling like it’s a miracle anyone is still alive at all. Health & Safety, Agrichemicals, gun safety – his real life close call stories are very entertaining!

Thursday and Friday were set for the new students to do the tractor theory so I had a very light week.

Out at Bannockburn Road the nets have gone on to protect the grapes from birds and the apple trees are groaning under the weight of all their fruit.

The glasshouse at the nursery is still empty and the vegetable garden is very overgrown. I’m sure we will be getting on to fixing that next week!

Last week’s weather (somehow I remember there being more rain…)


Summer Work Summary


Rainbow over Central Otago vineyard

During the Christmas break and summer holidays I worked for Vinewise. They are a vineyard management company who focus on using organic and bio-dynamic techniques. I was put with a group of regular employees who have a lot of experience as well as some other summer workers who were short-term and inexperienced like me. Unlike me, most of the short term workers had no interest in vineyards other than their weekly pay check, so I took advantage of the regulars time and asked lots of questions. I really learnt a lot. My supervisor was great and went out of his way to give me different tasks so I could gain experience, which also kept it interesting. I also found it interesting going to lot of different vineyards, everyone does things slightly differently.


Meet Artemis – one of the cows at Domain Thompson, bio-dynamic vineyard


Over the few months I had with Vinewise I have had experience:

Shoot thinning
Wire lifting
Straightening, tucking and clipping vines
Leaf/lateral plucking
Fruit thinning
Checking for powdery mildew
Taking leaf samples
Helping to make bio-dynamic preparations


Bio-dynamic shed at Domain Thompson


Sunrise at the vineyard. Bio-dynamic preparation 501 starts early!


Dreaded powdery mildew

Considering it was supposed to be summer, the weather has been terrible! There were lots of cold, windy, rainy days. Not great for growing grapes. Quite a few of the vineyards I worked at ended up with wind damage and powdery mildew. I have heard several people say this has been the worst summer in Central Otago for many years. Helicopters were a common sight around Cromwell, desperately trying to dry the cherries. Hopefully this means we will end up with a late summer.


Fresh snow on the hills – in summer! (It didn’t hang around long though)


Grapes starting to ripen

I didn’t get up to much gardening at home over the holidays but that didn’t stop our apricot tree from coming out in full force! We have so many we don’t know what to do with them all. The only other interesting bits in the garden are the tomatoes and lettuces I got from the Polytech plant sale, they have done really well. The strawberry plant was a total failure (not from Polytech sale), only one strawberry! Not sure what went wrong there…good thing I’m heading back to class…


Apricot tree at home


Term 4 -Week 7 – Final Week of the Year

Butcher’s Dam – spring in Central Otago

This was the last week of the term. Final exams have been completed and for most students that’s it for level 4 horticulture. Since I started half way through the year I will be doing terms 1 and 2 next year.

In propagation this week we pricked out more of the lavendar cuttings that have rooted into individual pots and then moved on to seed scarification.

Seed scarification is where you physically damage the seed coat to initiate the germination process. This can be done by nicking the seed with a knife, rubbing with sand paper or other methods of cracking the seed coat.

Kowhai seed pods

Kowhai (or Sophora) is New Zealand’s native flower. They flower in August and native birds love them. 

The seeds are inside pods. To scarifiy them we popped them out, gave them a rub with some sandpaper. They are a bit difficult to get a grip on so I ended up filing my nails at the same time. Excellent multitasking!

Then they were sowed into hygiene trays, covered with vermiculite and put on the heat bed to germinate.

Potting mix trial

On the final day we checked our potting mix trial. Tui All Purpose was the winner (far left), with no plant deaths, no weeds and plants growing well. Yates Thrive was the loser (second from right), which was suprising as it was one of the more expensive mixes. It had a couple of deaths and look at the weeds! 

In the afternoon we had a final field trip to Peter Brass’ property. He’s retired but you wouldn’t know it from his operation. He’s got two hectares of cherries, a nursery growing all kinds of plants and a paddock full of garlic and potatoes.



All sorts – lettuce, herbs, veggies

He sells his produce and seedlings at farmer’s markets all over Central Otago. He also grows sunflowers to sell as cut flowers.

It was so interesting to see how he’s set this all up. He has such a huge knowledge of plants and growing. I thought it was interesting how he has diversified and gets to do a bit of everything; orchard, flowers, seedlings, food production.

The weather has been extremely changeable this week. Rainy and windy one day, sunny and scorching hot the next. More of the sunny days please!

Last week’s weather:

The last two terms have been great and I have learnt a lot, both practical and theory. I can’t wait to come back next year.

Term 4 – Week 6 – Birds & Bees


This week there was a different topic everyday. On Monday we completed our tractor skills theory. I passed the theory test so I’ll be allowed to take one for a spin shortly, woohoo!



Inside the hive

Bees play an important role in horticulture – pollination. Even plants that self-pollinate seem to do better when bees pollinate them as well. Many crops must be pollinated by bees or they won’t produce anything, especially kiwifruit.

The cherry orchard at Bannockburn Road, which is 1 hectare, had 12 hives during the flowering period. They cost $140 each for 3 weeks. Beekeeping can be a pretty good business if you want to get into it. One hive can produce 50kg of honey a year, or up to 100kg if it’s a really good year. The thyme honey made here in Central Otago is very popular in Asia.

Bee’s life cycle and division of labour is really fascinating. The queen is the only fertile female. Her only job is to lay all the eggs but will only mate once at the start of her reign, and won’t leave the hive again. Although that’s her only job, possibly her more important function is producing a pheromone that keeps the hive happy and in control. Without it the bees could swarm. If she’s an angry queen the rest of the bees will be aggressive as well. A beekeeper will replace a queen if that’s the case. A queen will usually be replaced every 1 – 2 years anyway to keep the pheromone levels up and reduce the chance of a swarm.

The drones are the only male bees. There are only a few of them and they don’t have any duties except waiting around for a new queen to mate with. In commercial beehives this never happens since beekeepers will replace the old queen with one who has already mated. In winter, or if food is scarce, the worker bees will force the drones out of the hive. Poor old drones.

The worker bees are all sterile females. They are the ones getting stuff done! They will live for 4 – 9 months over winter but only around 6 weeks over summer. The first few weeks will be spent in the hive caring for larvae and the queen, storing pollen, making wax etc. Then for the last few weeks they will be out collecting water, pollen and nectar. Some of them will also be guard bees, guarding the hive: fanning bees, keeping the hive cool: robbing bees, stealing any honey they can find.



Worker bee in action

Bird Management:

Birds can do a lot of damage to fruit crops. They will swoop in once fruit starts to ripen. This is particularly problematic for fruit that ripens on the tree like cherries and grapes. Apples and apricots are picked mature, but not ripe, so they have less to fear from birds.

Cherries will need protection from the 1st of December and grapes from February onwards. Birds are active from sun up to sun down but are more of a problem during their natural feeding times: 6.30am – 10am and again 4pm – 8.30pm.

The worst birds for fruit damage in New Zealand are:

  1. Starlings – a flocking bird that will bring all their friends
  2. Blackbirds – solitary but smart. They will even burrow under nets
  3. Finches – small therefore hard to shoot and will peck once in each piece of fruit (how annoying!)

In the past growers would use poison to get rid of birds but there is a move away from that style of management. Some places still shoot birds but that can be easier said than done on some properties, especially if there are neighbours! Also nets and other facilities can get in the way.

Bird damage is worse around the edges of a crop, so smaller plantings are at more risk. Nets are probably the best option and can limit damage to about 5%. They are really expensive though, about $60k per hectare.

Other management techniques include:

  • Shooting birds
  • Removing tall trees from the property so they have nowhere to roost
  • Gas guns to scare them away with the noise
  • Mirrors/lights
  • Bird Guard – a speaker system that emits bird distress calls (extremely loud and horrible, I couldn’t work in a place with that noise!)
  • Reflective ticker tape – birds don’t like the flickering light
  • Self launching kites shaped like hawks to scare other birds away

New technology is coming into this area. Drones could be used and there’s a product called Agrilaser that shoots a laser at birds that makes them fly away.

We used a much simpler technique to get the birds out of the cherry orchard – making as much noise as possible and chasing them out of the netted area.


Shedding cherries

While we were in the cherry orchard I noticed some of the cherries weren’t looking too healthy. You can see some in the above photo look quite shriveled. Apparently this is a normal part of the process, if more flowers have pollinated than the tree can sustain some cherries will shed now, leaving the remaining fruit to get all the energy the tree can provide.


Grafted apple tree – success!

I checked in on the grafted apple trees this week. They are going quite well. Lots of buds have pushed and there is new growth.


Young cherry trees – UFO system

They young cherry trees are looking good. The posts and wires will go in soon so they can be tied down. Once that happens the side shoots should start to grow up. The swarth could do with a mow…

This week the weather has really packed in. Windy and rainy every day. The hills around Cromwell and Alexandra are finally green! The thyme is flowering everywhere giving the landscape a purple flush of colour.

Last week’s weather:


Term 4 – Week 5 – The Lettuce Company


Row after row of lettuces

This week all the horticulture students did work experience somewhere. I went to The Lettuce Company, a hydroponic lettuce grower just outside of Clyde.

It was a really fun week and I learnt a lot from Mark and his team. The greenhouses are huge and hold thousands and thousands of lettuces at all different stages of growth. They grow four different types of lettuce: green oak (the most popular), red oak, green frill and red frill.

The first task I was given was sleeving up lettuces to be sent to supermarkets. It’s pretty simple. Pull the lettuce out of the growing tray, pull off any undesirable leaves around the base and wiggle it into the sleeve. They get put into boxes of 10, sprayed with water to keep them crisp and stored in the chiller before being sent out.


Lettuces in plastic sleeves


Ready for harvesting

All the water and nutrients the lettuce need flows through the growing trays and is recirculated. They use very little water compared to other growing operations.

I also found it interesting that they don’t heat the greenhouses in winter, they actually just heat the nutrients that flow through the roots. It does get down to about zero degrees in there and some lettuces will get a bit of frost damage.

When I was working there the temperature was around 32 degrees. Since it’s getting warmer now as summer approaches they are going to start working at 5am to miss the worst of the day’s heat. In winter lettuces take about 8 weeks to mature, but only 6 weeks in summer. The seeds we sowed on Tuesday will be harvested for Christmas.

One of the tasks I enjoyed most was putting out the seedlings that were ready to be separated into the grow trays. The seeds are sowed into grow dam – a felt like substance that sucks up moisture and stays wet.


You rip off each little block and place it into the grow tray hole.


Since it has been quite hot recently we had to spend a bit of time taking some seedlings  out of the hydroponic system that had grown too fast. They will be stored in the chiller to slow them down and put back out when needed.

Timing is really important make sure the lettuces can be moved through the glasshouse as necessary, from seed to seedling, to ready to be harvested. As big as the greenhouses are there is limited space in each section so you don’t want all the seedlings at the same stage and nothing else in any other section.

It was great to go home at the end of each day feeling like I had achieved something and even had some lovely lettuce to show for my efforts 🙂

Last week’s weather: