Why do my Tomato plants turn purple?

A tray of our Funky Fresh Kitchen Tomato pots, College Challenger I think.  Getting a little "hard" i know.

We walk a fine line at this time of year, we lost the first two batches of Basil before even sending them out. The demand is so crazy that we have to try to have them available but it doesn't take much to put them off.

I've also had inquiries this week about Tomatoes losing colour. Perhaps more accurately taking on the hue of a three day old bruise, purple and yellow. This colouring is a symptom of the plants being hungry. Especially for nitrogen and phosphorus.  Tomatoes are a great crop, we have significant demand and they are relatively easy to grow except for the fuss of staking them. There are two issues that we have to watch for: stretching and black spots (haven't seen any yet this year!). To protect the plants from the winter and early spring elements we hold the plants in a poly house. This ensures the plants can grow without stress but encourages them to grow very tall and skinny and if the foliage is too soft the black spot bacteria can infect the plants easily. We try to control this culturally by deliberately under watering them and by supplying only just enough fertilizer to keep them green but not enough to grow like crazy. Another trick is to use what is often called a 'native plant' fertilizer that is very low in phosphorus, this encourages strong cells and inhibits 'stretchy' growth.

When the plants get too hungry they start to change colour: yellow foliage indicates plants need more nitrogen and the purpling is a sign that a little phosphorus is needed. In fact in the nursery this colouring is quite a good sign because we know we can generally turn these plants around very quickly with a little extra liquid feed. But here's the down side, when we are managing plants so closely they can start to look very hungry very soon after leaving our loving care. Now that the weather is warming we can take a calculated risk and move plants outside sooner, this hardens them up naturally and allows us to start applying a little extra fertilizer. In the garden centre a weekly application of complete, liquid fertilizer should help maintain colour and shelf life but I understand that this is not always possible.

For gardeners, a little yellow and purpling is not at all a bad thing.  Once plants hit freshly prepared soil or quality potting mix they jump away, I'd suggest much more reliably than plants that go into the garden too soft. Just make sure it's purple shading, not small dark spots.

Hope this helps, please don't hesitate to call if I have only raised more questions.

Garden Favourites in Summer

Happy New Year!



A couple of old favourites have bobbed up again this week. By chance Kerry proudly showed me a couple of Tomato plants I had taken home. I delivered these "spotty" plants and said I was keen to see if we could out grow the bacterial spec once the plants were in the ground. The Boss has done the rest very successfully and very simply. Cleaned off the infected foliage and top dressed around the plants with about a shovel per plant of Chook litter (litter, not raw poo). They are growing vigorously now, about 1m tall each. That's it! I'd prefer this wasn't an issue but I'm still getting questions about spots on Tomato leaves so it's nice to be able to say there is a practical solution.

The other favourite is

I was just wondering if you have any idea why I rarely ever get any female flowers on my pumpkins?  Is there a particular nutrient that produces female flowers?  I get plenty of male, but they're not that useful without the females!

Warmest regards

Sherilee

I checked with Dangerous Don who confirmed this is a common and inconsistent problem and recommended we just wait. I also checked back on my previous Newsletters and discovered I have written about it previously! Any way I had delayed answering Sherilee about a week and by the time I had suggested "pruning" the Pumpkin tentacles, 6 female flowers had appeared of their own accord. My theory is Pumpkins and other Cucurbits wait for a check to their growth before deciding it's time to reproduce. That could be the weather getting hot or someone amputating a few limbs.

Best wishes for a safe, prosperous and Happy New Year.

Ornamental and Culinary Chillis

May, June & July are always a little frustrating, even angst ridden.  No matter how I try I have never been able to finish our planning for spring on time... like back in May.  Well it's the same this year, I'm still fussing over the final details of a plan that should serve us for the next 12 months.  Really I should be well into organizing seed and label orders, all of which need to be done in advance.

Of course all of that makes this the most stimulating time of year as we look at what we have done and what new things we want to try.  This year we are looking at expanding the range of Chillis and Capsicums we grow.  Now I know it's a little early to start talking about plants that you don't expect to start planting until September at the earliest but we have been sowing various Chillis for 3-4 weeks now, so I'm on a roll.
     


We are offering more Chillis because of the intense interest they have generated over the past 2 years, particularly the question we continually answer: "Can we eat ornamental Chillis?"  We have decided that our habit of identifying Chillis as Ornamental or Edible creates the confusion so from now on we will use the terms Ornamental and Culinary.  Genius! Yes, now everyone will understand!  Perhaps not, but the idea is (to my knowledge) there are no poisonous Capsicums, but there are plenty that taste terrible.  Our rep Di who is a real foodie has tested this theory and supports it fully.  Of course, just because a Chilli tastes terrible doesn't mean it isn't hot.  Chilli heat is a quite separate thing to taste and I should point out that not all ornamental Chillis are hot.

Now, I have said that to my knowledge there are no poisonous Chillis but I do need to remind you that Capsicums and Chillis are from the Solanaceae family that includes Tomatoes, Potatoes and Deadly Nightshade.  The leaves of these plants are poisonous to greater and lesser degrees so I don't recommend eating the foliage.

Just to add to the complexity of this group of plants we produce them for sales in two distinct seasons.  The first is the culinary Chilli and Capsicum Season.  We start selling traditional varieties like Capsicum Californian Wonder and Chilli Red Hot Cayenne in August for enthusiasts with green houses to protect their crops.  Although I generally regard the Capsicums as hardier than Tomatoes, at least they tend to suffer fewer growing problems they are less vigorous than their pomodori cousins in cold weather. Both will Capsicums and Tomatoes turn quite black at the slightest hint of frost.   These are the young seedlings we offer in punnets and the more advanced plants in single 100mm pots.

The second season is for the ornamentals.  Of course this is really just the fruit of our earlier labour.  We hope to produce brightly coloured fruit by Christmas from the plants we first started sowing back in May, generally though we expect our Chillis will produce their best colour in January and February next year.  The development of the fruit is fascinating to watch as the small green berries fatten into more recognizable Capsicum fruit and the colours come, then go, then finally take on their mature colours which range through yellow, orange, fire engine red to purples and black.  Eventually the fruit dries and shrivels on the plant, it will usually hold its colour to this stage.  When the skin has dried like this the seed is ready to collect and should be quite viable to produce a new crop although I can't vouch the new plants will be true to form if you have been growing a selection of different Capsicums in one area.  Keep in mind that Capsicums as a group are actually short lived perennial plants that can be over wintered in Victoria and will produce successfully in the second and possibly third season if they are re-potted or at least given a cut back and a good feed. 


So why do we identify some Chillis as ornamental?  They have been bred to be used purely as ornamental plants, generally the plant will be more compact and carry a lot of fruit in bunches that are particularly striking.  Flavour is ignored altogether. We have done a little research this year  and have found a few culinary varieties that produce attractive, compact plants so we'll see how they go come December and January.  The pic above is Capsicum Courtyard a great tasting Pimento (heart shaped) Capsicum with the added benefit of growing on a very attractive plant.

Year 8 History, Medieval Crop Rotation

I haven't had much response to last week's request for suggestions on crop rotations except for Laurie who plans to grow his Toms in 500mm pots next season because his soil is infested with either Fusarium or Verticillium.  Follow the link if you want more detail on either of these diseases but for our purposes the symptoms are very similar.  Fusarium is more noticeable in warm conditions, Verticillium when it is cool. Both of these fungi enter the plant through the roots and damage the stem of the plant choking off supply of water and nutrient to the foliage causing wilting and eventually plant death.
        
Fusarium wilt symptom and a pic showing damage to the plant stem.
Picture from Plant Pathology on line
A common solution, in fact the ancient solution is to rotate crops.  That is, avoid growing Tomatoes (or Potatoes and possibly Capsicum & Chilli as they are all related) in the same soil year after year.  Laurie has been using a 3 year rotation for his Tomatoes but has found that even this is not enough... I still remember 3 field rotation systems from year 8 history.  'Barney' Rundle made a great deal of this fact, I have no idea why.   Any way the crop rotation idea is that the fungal spores will eventually die after a few seasons if they don't find a host plant to grow and reproduce in.  But spores and seeds are fantastic plant survival agents and can survive terrible conditions for remarkable periods, just look at the wild flower shows in Central Australia (I hear the Todd river is in flood so we should see news reports of the "desert in bloom" in the next few weeks).  As we learned from Mr Rundle the three field system, one year with one crop, one year with another and the the third fallow was both inefficient and eventually unsuccessful in controlling disease.

From my reading most vegie gardening books recommend disease resistant cultivars.  This brings us back to the old question of Heirlooms vs. Hybrids.  Laurie's favourite Tomato is a classic Heirloom, Brandywine.  Half Kilo fruit if you believe him, pink skinned and solid fleshed.  Actually Laurie if you're growing fruit like that why change your system?  From my experience disease resistant varieties only offer a limited defense against heavily infested soil.

Brandywine Tomato pick from tradewindsfruit.comFollowing last week's newsletter note the cracking on the shoulder of this fruit.
Now there is one other method for protecting your garden plants from soil borne diseases: Fumigation.  Yes it is as bad as it sounds.  When we cleared out my grandfather David's garage I found a 4' tall cylinder of  Methyl Bromide.  This is filthy stuff that used to be used to kill every living thing in the soil for commercial vegetable and flower growers.  Clearly Dave had brought some home.  Well you know, he loved his flower beds.  Any way I'm sure Methyl Bromide has been banned altogether now.  Interestingly because potting mix can be "picked up" it can be steam pasteurized killing most harmful organisms but leaving the "media" inoculated with helpful bugs.  This is a bit beyond the home gardener.
So back to Laurie's original suggestion. Grow Tomatoes in big pots.  I think it's a great idea but not cheap.  If you use pots you must use good potting mix and Laurie is proposing pots twice as big as Kerry used at home this year so that's a lot of potting mix.  Of course you will remember that Kerry's 250-300mm pots just weren't big enough to supply enough nutrient or water to advanced Tomato plants.  And since we're talking about crop rotations the potting mix needs to be replaced for next year's crop or the benefit will be lost and don't forget that the big pots need to be washed out with disinfectant to ensure that all the fungal spores are gone.

That feels like a lot of reading today, see you next week I've got a great idea about attracting Lady Birds and other insect predators.
Oh and Happy Birthday to Laurie who turns 81 on Wednesday.

The Definitive Pumpkin Solution!

On making pumpkins etc. produce female flowers I learnt from experience that you need to take the ends off the leaders, thus producing more laterals. I discovered this when I had a feral pumpkin that grew in the compost heap years ago. Only had male flowers on 15 foot leaders that were threatening to take over the garden, so I went round the bush with a shovel chopping the "arms" off to about 4 feet. Voila! - laterals covered in female flowers! I seem to remember I got about 20 pumpkins from one vine. So now I'm brutal with them, but make up for it with LOTS of compost and horse manure.Jenny
How good is that!  Thank you Jenny, I'm happy to call that the definitive Cucurbit growing tip.  I'm sure you can't get simple, practical advice like this from a Google search (well, hopefully you can now).

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I also received this question during the week:
"

While we have been eating our own tomatoes for the last month (& they are very tasty), the ones in pots (which were doing OK) have all developed circular splits around the fruit & I don't know how or when it happened. Obviously they can't be fixed & luckily many of them are still edible. I think I probably didn't keep heeding your feeding advice, & will try to do better next year.

As I only have 2 smallish plots (about 2m x 1m each), rotating my crops is a bit of an issue. Can you offer any thoughts?

Deirdre"

Follow this link to the original pic on filkr.com

The concentric splits are unfortunately all too common, along with long radial splits don the sides of Tomato fruit.  This is what we call a disorder, not a disease.  Tomato fruit development responds to varying growing conditions with bursts of growth followed by less active periods, a bit like my son Ben at the moment (fortunately he's not cracking, just stretching).  Some varieties, frequently heirloom varieties are much more prone to this problem than others.  It appears that plants that mature their fruit hidden in the foliage are less susceptible.

Older (50's & 60's I guess) seed catalogues made a big deal over the resistance to splitting and cracking of the latest varieties.  We see much less of this today because it is generally assumed that this won't be a problem with modern hybrids.

As mentioned cracking is not a disease and the plants are perfectly edible as Deirdre has found. The only problem is that the cracks can provide an entrance for a disease infection so the fruit can go off more quickly.  Of course this leads to the old argument over the relative benefits of modern hybrids and their open pollinated predecessors.  Keep in mind the breeders of the Heirloom varieties pretty much ignored anything but flavour, hybrids are often accused of ignoring flavour in the search for the benefits of long storage.

OK, that's part one of Deirdre's question.  How can crops be rotated if there is only a limited space available for growing.  My real expertise is in growing in containers, so this isn't an issue I regularly face.  If you have any good suggestions I would love your feedback.  Please send me an email or leave a comment on my blog and I'll reward feedback with a tray of vegie seedlings (Um, well that's if I can get them to you. Victoria, Australia works).

The Classic Tomato problems

I worry that I spend too much time talking about Tomatoes, but I’ve received two classic Tomato questions this week.
Why do my Tomato plant flowers drop off and not set fruit?
Why have my Tomato fruit gone black at the base? Lisa brought the fruit pictured into work.
Well follow this link for the answers to both these questions. It turns out that I answered them both in February and it’s interesting to see how this newsletter has developed over that period.
The pic is new, Lisa brought this Tomato into work and photographed it for me.