Why does my Coriander bolt to seed?

Last Sunday my son, Ben and I spent the day at the Frankston Toy Library’s Teddy Bear’s picnic. Fortunately it didn’t get too hot. Ben and I run a free “pot a plant” stall. At community days they usually have the petting zoo, which Ben loves and I let him sell off surplus plants to the parents who can’t help themselves. Sadly Ben has had a lesson in free market economics this weekend; he has at previous fetes pocketed as much as $100.00 which is immediately blown on computer games or Lego. On Sunday, with the nursery industry in the doldrums he took less than $20.00 (and I am too mean to pay for his services). We potted flowers and vegies all day with the kids, but their parents just were not interested in buying this time.
Any way, I like potting days because I meet gardeners and I can work on building our newsletter mailing list. The standout question from the weekend was, “Why do my vegies bolt to seed?” On the spot I found this difficult to answer properly and having done a little research I know why. This is a common symptom but the reasons vary depending on the vegetable variety.
Let’s focus on Coriander today.
Coriander is from the Carrot and Parsley family. It originates from southern Europe and the Middle East and is widely grown and used throughout Asia. You would imagine that it likes hot weather. However, Coriander is a classic annual. If it is stressed its first priority is to set seed and ensure the survival of the next generation. In its natural Mediterranean environment stress is most likely to come from heat, so extreme heat is a common trigger for Coriander bolting to seed.
How do you prevent this? Minimize plant stress. Provide light or dappled shade in the hottest part of summer, make sure plants are well watered and take extra care transplanting. Many sources recommend direct seeding to prevent transplant shock. Of course I would prefer that you didn’t use this option and remind you that direct seeding is fine, as long as you get good germination! Germinating can be the trickiest part of the job.
By the way, a number of people have suggested just cutting the flower stem out and continuing to pick the leaves. Another thought is to pick the stem before the flowers open. The stem is very flavorsome (actually this suggestion was for Bok Choi, so if Coriander tastes terrible I’m sorry).

Zucchini revisited

A few weeks back I asked if any body had experienced Zucchini Black Jack growing rather attractive, but completely wrong, round fruit.

I had a number of responses to this question, fortunately no gardeners have had the same experience. I wonder now if our staff who took the plants home and reported the problem did not take plants that we had trial grown. We tested this seed first because it was old, my friend James had given me a stack of seed he no longer needed. Unfortunately the Zucchini did not germinate properly so we chose not to use it. Perhaps some members of our team, always on the lookout for a bargain snaffled the few plants that did grow.

Anyway, a number of correspondents did report Zucchini problems this season. In particular: “Why do some of them rot from the flower up? A customer swears that it's not a water problem and I must admit that a few of my own have done this but not all of them by any means.” I think, and a little research agrees that the symptom is very similar to Blossom End Rot in Tomatoes. Blossom End Rot is a response to irregular soil moisture, especially when transpiration rates are high (hot dry conditions). This problem is accentuated if the dry conditions are preceded by a period of high moisture (Think December in Melbourne). The fruit grows so quickly that the water requirement of the plant cells cannot be met, so the cells collapse. They may or may not then pick up a secondary infection.

Tricky problem to solve in the current climate, our rain water tank is now dry. The only real solution that I have is get right on top of your water management. Mulch! And don’t forget that drip irrigation systems are both highly effective and usable under the current water restrictions.

I need a new dispatch person

I have a really tight little team here at Scotsburn and I need someone to fill one of our cornerstone operational positions. I need someone who can work quickly with a high level of detail; can work all day in all weather and still have time to enjoy matching colours and plant textures. Our dispatch person must be organized and be able to maintain focus and discipline when there is a long list of orders still to be packed and a truck already waiting to be loaded. For the right person this gets the blood pumping, for the wrong one it’s just frustrating. If you think this might be for you please follow this link

Vinca can save your life... or take it

I took a call this week. A lady was asking if the Vinca she had bought in a Scotsburn punnet was also known as Madagascar Vinca. Initially I said “I don’t think so, but I don’t know”. So while she explained her question I started to Google search. The answer is yes. The full common name for Catharanthus roseus is Madagascar Periwinkle. So…
Well my phone correspondent happens to originally hail from the Seychelles (complete with soft French accent) where Madagascar Vinca has naturalized. Just remember that point, I’ll get back to it. The lady with the attractive French accent used to drink tea made from Vinca leaves steeped in boiling water when she was a child in the Seychelles. She wanted to know if this was the same plant so she could make tea.
“Well, yes it is. Does it make nice tea?”
“No, it’s terribly bitter. We called it rosé amère which means bitter rose, but nobody in the Seychelles ever gets Leukemia”.
So with a little more searching it turns out that Leukemia treatment drugs Vincristine and Vinblastine have been extracted from Vinca.
Now before you go rushing off to make a cup of Catharanthus tea to reduce your white blood cell count, just keep a couple of things in mind. This stuff is toxic, so too much will make you very sick and I have found serious warnings about inappropriate use of the drug Vincristine.
Plus, remember I said that Catharanthus roseus has naturalized in the Seychelles, well it is closely related to Vinca major and V. minor. V. major is a declared weed in Victoria. Our cool climate controls the spread of Catharanthus down here so it is not a problem, but it is considered a weed in tropical Queensland. Please keep an eye on any self seeding plants.
Sadly the lady with the sexy French accent didn’t leave her name.

Bill's Tomato flowers

I have an old friend, Bill. Bill must be 80 plus and very deaf. I don’t remember when we first met but whenever I attend the nursery industry’s monthly trade day Bill makes a point of stopping to say hello.
In December Bill asked me why the flowers on his Tomatoes were dropping off and no fruit was developing. Now the standard reply is “no pollination, possibly no bees”.
The options are to tap the flowers with a pencil or finger to release the pollen. If you are really serious, a fine brush will pick up pollen from one flower and release it on another. Plant breeders still regularly use the brush method to ensure they can control which pollen lands on which flower. Greenhouse Tomato growers use a vibrator on the plant stems to release the pollen; this option always raises a smile.
The question remains, why are there no bees in Bill’s back yard?
Bill came to say hello at trade day this week. “You don’t know how stupid I’ve been” he tells me.
“Why do you say that?”
”Well, you know you told me the bees were not pollinating my Tomatoes?” I must admit I had forgotten. “Well it turns out that the Tomato plants are next to the lemon tree. I had put a sticky trap out for the citrus gall wasps and what do you think was stuck all over the trap? ..... Bees!”
I must be honest I am surprised that Bill’s sticky trap caught so many bees. I thought that traps are really designed for monitoring populations, not controlling them but it just goes to show how little things can throw nature off balance