August 2022 – The Garden Professors™

The 2022 Tropical Season: It’s Alive!

In my last blog post in early August, I noted how quiet the Atlantic tropical season has been so far this year. In fact, the period from early July through this week has been one of the quietest on record, with no named storms since the short-lived Tropical Storm Colin formed along the South Carolina coast and dissipated less than 24 hours later on July 3 in eastern North Carolina. The last time we had so few named storms was 40 years ago, so while it is not unprecedented, it is certainly unusual. And we are definitely later than the average date for the first hurricane of the year. By comparison, in 1992, a strong El Niño year, Hurricane Andrew (an “A” storm, so the first of the year) had formed and taken its devastating track through southern Florida and Louisiana by this date.

All of that is about to change, and hurricane forecasters are relieved after predicting a season of above-normal activity based on warm ocean temperatures and the current strong La Niña. They could still be correct. The National Hurricane Center’s 5-day map (as of 8-28-2022) is now showing four areas of potential development, with one area that has a 50% chance of development into a tropical depression within the next 5 days. Just in time for the peak of the season, according to the timeline we discussed earlier this month.

Why have the tropics been so quiet?

What caused the very quiet period in July and August? Hurricane climatologists point to several factors: the continuing clouds of dust that have blown off Africa and across the Atlantic Ocean towards the west, dry air moving in from Europe, which is experiencing its worst drought in 500 years, and the lack of strong waves moving off of Africa to act as seeds for tropical storm development. But the presence of warm sea surface temperatures and the lack of a strong jet stream (which is consistent with the presence of the La Niña) were expected to contribute to a stronger season than we have seen so far. If we can’t understand why this season has been so quiet so far, it means we still have a lot to learn about hurricane climatology and behavior.

A large storm in the ocean

Description automatically generated with low confidence — *Tropical Storm Lisa on September 23, 2016 with African dust*

The second half of the 2022 season is likely to be a lot more active than the first half, although forecasters have dropped the predicted number of storms from the early forecast due to the past two quiet months. If you live in an area affected by Atlantic hurricanes, you should be prepared for a more active pattern—don’t let the last two months fool you! If you live in another part of the world that is affected by tropical storms, you should also understand their climatology and likely impacts on where you are as well.

A body of water with a sunset

Description automatically generated with low confidence — *Caribbean rain shower at Man-of-War Bay, Tobago, September 1980. Source: NOAA.*

Some resources for following hurricane weather

For those of you who are fascinated by tropical storms and hurricanes, even if you don’t live in an area that is prone to them, there are a few resources that you can use to track potential storms and follow them as they develop and move through areas that could be severely impacted by them. The first site I use is the National Hurricane Center, the source of official forecasts and outlooks for the season as well as specific storms as they form. Their website has a lot of information about past storms as well as educational resources on tropical systems. You can also find a lot of maps and climatological information at Mike’s Weather Page if you just need a quick look at maps and other images related to tropical weather in the Atlantic and Pacific Basins.

On social media, I follow Bryan Norcross and Brian McNoldy on Facebook and Twitter; they may be on other social media as well. Bryan Norcross is the television meteorologist who was working in Miami at the time of Hurricane Andrew; it has been fascinating this week to follow his timeline of Andrew from tiny disturbance to monster storm as it hit Miami and then Louisiana over the past week back in 1992, thirty years ago. Brian McNoldy is a senior hurricane researcher who works at the University of Miami and has done some interesting climatological work on past hurricanes as well as provides insight on the current season. There are also plenty of great local resources for local impacts if you live in a hurricane-prone area.

A picture containing nature

Description automatically generated — *Landfall of Hurricane Michael, October 10, 2018 from earth.nullschool.net*

How to visualize the wind

If you are interested in looking at the wind patterns associated with storms, both tropical and extra-tropical, then there are three sources of fascinating maps that allow you to visualize the flow of air across the United States or the world:

United States current surface winds Hint.fm/wind. This site has a current map of the surface winds across the continental United States showing the wind speed and direction in motion. It is based on a near-real-time computer simulation to provide seamless coverage across the country.

Global earth interactive wind map https://earth.nullschool.net/. This interactive map allows you to look at current winds anywhere on the earth by dragging and zooming on the globe. You can use the menu on the lower left to pick higher levels in the atmosphere; this will allow you to look at jet streams aloft as well as surface winds.

Windy global current and forecast winds https://www.windy.com/. This site provides global current and forecast winds as well as other weather information that will allow you to view the weather and plan for future weather conditions at home or away.

These sites provide you with information about both wind speed and direction. That can be very useful for gardeners who are spraying or need wind information to track where the air hitting their gardens has come from. Wind drift of agricultural chemicals also causes damage to crops and outdoor workers. Exposure to chemicals such as weed killers can affect gardens adversely, and it can be important to know where those chemicals are coming from. If you don’t have access to local wind observations, these maps can provide you with useful information.

People and Plants

In this episode of P&P we’ll take a look at the life and career of the aptly named Nehemiah Grew, the “Father of Plant Anatomy”.

Nehemiah Grew was born on September 26, 1641 in Warwickshire, UK. He graduated from Pembroke College, Cambridge in 1661 and ten years later was awarded a MD degree from Leiden University in the Netherlands.
His interest in plant anatomy began to bud in 1664. In 1670 his essay, The Anatomy of Vegetables begun, was shared with the Royal Society and resulted in his election to the membership.
By 1672 he’d put down roots in London and soon had a large medical practise. Even though he was busy with his career as a physician he still found time over the next decade to write a couple of books, a few short publications on botany and several papers one of which has the intriguing title, “Comparative Anatomy of Stomachs and Guts” and was included in his “Catalog and Description of Rarities” publication, ca. 1681.

Photo courtesy of Royal Society (Great Britain) Museum.

In 1682 his tome, “The Anatomy of Plants begun as a philosophical history of plants“, was published. It’s largely a collection of previous publications and is divided into four books, Anatomy of Vegetables begun, Anatomy of Roots, Anatomy of Trunks and Anatomy of Leaves, Flowers, Fruits and Seeds. It has eight-two illustrated plates and an appendix of seven papers which deal mainly with chemistry.
The book is noted for its descriptions of plant structure, a fairly unknown thing at that time. Grew described nearly all the key differences of stem and root morphology and showed that the flowers of the Asteraceae family are composed of multiple tiny tube flowers (florets). The most amazing of his discoveries was that plants reproduce sexually and that flowers are sexual organs. He distinguished and assigned “roles” to the calyx, corolla, pistils, and stamens.

Grew is remembered for being one of the first to establish the observational basis for botany and is noted for his detailed descriptions of plant anatomy. He utilized the microscope (invented in 1590) for his plant anatomy explorations and was a pioneer in this field. His book “Anatomy of Plants…” contains the first known microscopic description of pollen. He discovered that although all pollen is roughly globular, its size and shape varies between species; however pollen grains within a species are all alike. This discovery is central to the field of Palynology, “the study of dust”, which is the study of pollen and particulate samples both organic and inorganic.

Plate from Nehemiah Grew’s *The Anatomy of Plants* (1682)
Source

Grew’s research technique was based on his adherence to observations and avoidance of explanations invoking occult, hidden or vital forces, or signatures. He also avoided the direct hand, intervention, or guidance by God or other spiritual beings.
He embraced a mechanical and natural philosophy which permitted him to think much like an engineer or how to make the most out of the materials at hand. This engineering concept was theologically acceptable during his time.
Why is this significant?
This ‘Mechanical way’ and Grew’s own theory of “Organ-ism”, that plants possess organs and structure, was outside the bounds of most of the thinking of his time. Before the 17th century it wasn’t certain that plants had much internal structure and that distinct parts or organs played distinct roles. It was often thought that the external shape of a plant was a clue or signature to its use, re: Doctrine of Signatures. But whether there was anything resembling organs in plants was contested. Grew’s detailed illustrations help dispel that belief and bring the study of plants into the scientific world.

In honor of Nehemiah’s work and role as a founder of modern botany, Carl Linnaeus named the genus Grewia after Nehemiah Grew. Grewia is in the Malvaceae family and can be found in several areas including Africa, India, and Australia where it has naturalized and become invasive.
Its fruit comes in both sweet and tart varieties and is used for food and beverages. Other parts of the plant have been used medicinally.

Grewia occidentalis
Image by Giuseppe Mazza

Like to know more?
Part 1 | Christoffer Basse Eriksen: Nehemiah Grew and the Making of the “Anatomy of Plants” (1682) – Lecture

Part 2 | Christoffer Basse Eriksen: Nehemiah Grew and the Making of the “Anatomy of Plants” (1682) – Response & Panel Discussion

Fair Judgement: garden lessons from a fair (and crop trial) judge

I love a fair! Which is a good thing since I find myself at a lot of them as an extension professional. It seems like fairs attract extension folks like honey attracts flies. We’re always involved in the 4-H activities – the livestock, project displays, and contests. Sometimes we pop up other places as well. The one thing that I get asked to do multiple times each summer is act as a judge for horticultural entries. Usually for 4-H youth entries, but sometimes for the open class where anyone can enter their best (or sometimes not so best) produce, flowers, and more. I thought I’d take a few moments to talk about what I look for as a judge, so if you ever want to enter your best tomatoes or dahlias at the fair you’ll know what to do to get the best ribbon possible. And even if you aren’t going to enter something into the fair, the rules and guidelines we use can help you select quality seeds and plants for your own garden or help you pick out the best produce at the grocery store or farmers market.

Produce items and flowers with their ribbons after judging. Each item is judged on its own merits and is not compared to the other entries (except for selection of a “grand champion” or for submission to the state fair).

The fact is, many of the same qualities I look for and skills I use when judging produce and flowers at the county fair are also ones I use as a trial judge for the All-America Selections (AAS) program. I recently attended the AAS/National Garden Bureau/Home Garden Seed Association summer summit and was discussing fair judging with some folks from seed companies. They were excited by the process, and especially by the fact that one of the things that I judge (and have gotten fairly strict about) is that the fair entry information contain the cultivar or variety name. They found this exciting because companies, especially smaller companies, put a lot of work into developing new cultivars, and when the general public identifies specific cultivars as being high quality (as in, I grow XXXX cucumbers because I think they are the best) or at least being able to identify the qualities of specific cultivars then it is sort of like a recognition of the plant breeders and distribution company’s work (and also puts money in their pockets). As home gardeners, it is important to know which cultivars or varieties work best for you and to be able to identify the qualities you prefer. It can also be handy to see cultivars out in “the wild” and be able to recall the name of plants you like, which is why the All-America Selections program has display gardens where you can see the edible and ornamental winning plants up close and personal. I’ve written about the trial process for this blog before.

Our display garden on the UNL Campus, which is our home garden for our TV show Backyard Farmer. We feature the garden each week on the show, which is one of the longest running locally produced shows in the US celebrating its 70th anniversary this year. Watch episodes.

Now back to the fairs – this year I used my judgmental eye at five county fairs in the course of three weeks – with three of those fairs in one week. I’m not sure why I’m so popular, maybe because I’m good at it or maybe because nobody else will do it. In either case, I do my best to not only judge fairly and by the rules, but also provide valuable feedback as a learning opportunity for youth. The whole point of fair entries and projects, from our point of view at extension, is not that a kid gets a blue ribbon (in Nebraska the top standard ribbon is purple, though, which I had to adjust to) but that we help raise blue ribbon kids. In some counties I actually talk to kids, interviewing them on how they grew stuff and giving them feedback on their entries. When I don’t interview, I fill out a score sheet and provide comments on positives and negatives of each entry.

Here are a few of the things that I look for when judging, and how they might help home gardeners:

Overall quality, appearance, and health – this is the one that most can identify with. Does the produce item or flower look appealing and high quality. Is it free of blemishes, diseases, bug holes, etc. You’d be amazed at the quality of some things we get at the fair. Of course, since I usually judge items for kids I do try to provide feedback on how to improve quality overall. Basically, my reference point is “would I buy this at full price a the market or grocery store”.
Correct preparation – this is one where lots of folks get tripped up. For produce items we are often looking for whether or not the item has been harvested correctly, whether or not the stem has been removed or trimmed properly. It varies by produce item. These rules seem superfluous and overkill, but they actually are based on guidelines for how to best prepare produce and flowers to extend their shelf life and storability. For example, in Nebraska our guide says to leave a ¼” piece of stem on cucumbers, to remove the blossom cap/stem (sepals) from tomatoes to reduce damage to fruit, to trim beet stems to 2”, to pull (not cut) rhubarb and leave 2” of the leaf blade attached, and so on and so forth. These guidelines all help reduce damage to produce items or keep them fresher longer – so these guidelines can be handy for home gardeners, too. Herb stems are to be cut a certain length and kept in water (like a bouquet) with the leaves below the water line removed. For flowers, rules will often state how large of a specimen to provide, and to remove the leaves below the water line. Rules vary by state and by fair, but many of them are fairly consistent here. You can find our Nebraska preparation guides for produce and flowers to see how best to harvest and prepare crops and flowers for storage or usage.
Uniformity of size, shape, color, etc. – this one also trips a lot of people up. First, most fair rule books will state a specific number of one item that needs to be provided, so that a judge may judge consistency and uniformity across multiple specimens. For example, our fairs require two specimens of larger produce items (slicing cucumber, zucchini, eggplant, etc), five specimens of medium size items (slicing tomatoes, carrots, potatoes, pickling cucumbers, beets, etc.), and twelve specimens of small items (cherry tomatoes, string beans, etc.). Flowers usually require five stems, but larger specimens like sunflowers may only require three. All the specimens provided in the exhibit should be as uniform as possible. All of the produce items and flower stems should be exactly the same size. Being the same level of maturity is also important and also leads to uniformity of color, especially in produce items. Color uniformity is especially important in flowers. I use this uniformity rule when judging our AAS trials as well – do the plants perform consistently across the whole plant in terms of harvest or flower appearance. This is a useful skill for home gardeners as well, as you can judge how well a specific cultivar or variety performs for you. You want to grow plants that perform well and provide consistent produce or flowers and not plants that only produce a few good items here and there with questionable produce or flowers mixed in.
Correct identification and cultivar names – as I stated earlier, the correct identification of the plant (like don’t enter a jalapeno pepper as a bell pepper) and the cultivar or variety are important. Knowing what the actual end product is supposed to look like is helpful for gardeners to know what they are growing, understand the traits that they want in the plants, and how to select the seeds or plants with the traits they desire. That’s why the seed company reps got excited about this part – because having gardeners identify specific (newer) cultivars as the ones with the traits they want is important. It takes garden selection from “I want a slicing tomato” to “I want this specific cultivar of tomato because I know it does X, Y, and Z, so I’ll buy it from this specific seed company that sells it. That in part is what we do with the All-America Selections trials. We try out new things (before they hit the market) to test them out for taste, color, disease resistance, and a whole bunch of other things to give a “stamp of approval.” So any time you see that AAS symbol you know there have been several judgmental eyes (including mine) have assessed those plants and found them worthy.

So next time you visit a fair take a look at the exhibits to see if you see what a judge looks for. And think about entering your produce or flowers in a fair near you just to see how your garden skills stack up with your neighbor’s. Even if you don’t win best of show you can have fun and learn a bit along the way. And even if you don’t enter at the fair, you can use your judgement to pick the best plants for your garden for years to come.

Sometimes you get to judge the “fun” stuff, too….like best dressed vegetable.

The 2022 Tropical Season: What are Tropical Systems?

In the Southeast, almost nothing gets more press than the Atlantic Tropical Season, including the outlooks, real-time events, and post-storm analyses. If you live in another part of the United States or the world, you may not be as directly affected as the Southeast is, but you might be surprised at how far and wide tropical moisture is spread, either directly by tropical storms and hurricanes or by the remnant moisture which can be carried with the winds for long distances away from their original sources. This week I will describe what tropical systems are and what they mean for gardeners. In my next post, I will review the current season, including any impacts that have occurred. Don’t let the early quiet conditions fool you—about 90% of Atlantic tropical activity occurs from mid-August through mid-October.

Hurricane lily (*Lycoris radiata* var. *radiate)*. Source: Tonbu Mizo, Commons Wikimedia. For why they are called “hurricane lilies”, visit https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/hurricane-lily.html.

What is a tropical system?

I am using “tropical system” as a term that encompasses the life cycle of a tropical disturbance from birth to death. That may include formation by a tropical wave coming off Africa, developing in the Gulf of Mexico, or growing in the Eastern Pacific Ocean, then a tropical storm, a hurricane (maybe even a major one), and eventually a slow death as a tropical depression or extra-tropical low that has lost its tropical characteristics.

The map below shows historical tracks for all known storms across the globe. Note that in some regions they are called hurricanes and others, typhoons, but both are tropical cyclones, the generic name for rotating, organized systems of thunderstorms that originate over tropical waters and have closed, low-level circulations. The pattern of tracks shows some interesting information about tropical systems. For example, why are there almost no tracks in the eastern part of the South Pacific Ocean or in the southern Atlantic? Why do many of the tracks show a curve as the storm moves from east to west? Why are there more storms in the Northern Hemisphere (NH) than in the Southern (SH)? Why are there almost no tracks along the equator?

What ingredients are needed for tropical systems to develop?

Tropical systems form from areas of low pressure that develop rotation (counterclockwise in the NH and clockwise in the SH) as the storms’ pressure decreases. For the storm to strengthen, it needs favorable conditions to cause rising air in the center, which drops the pressure at the surface. One ingredient is ocean surface temperature of 80 F or higher (27 C)—that explains why almost no storms develop in the southeastern Pacific or southern Atlantic, since both are far too cold. Tropical storms and hurricanes are considered to be “warm core” systems with the air in the center of the storm staying warm all the way to the top of the circulation. The peak season of storms in the Atlantic is related to the cycle of ocean temperatures, with the highest likelihood of storms in the period from mid-August to mid-October. As ocean temperatures warm, this could mean a shift in hurricane season in the future.

For spin to develop, you need a force called the Coriolis force that affects the atmosphere due to the earth’s rotation around its axis. The Coriolis force is zero at the equator so any areas of low pressure that form in that area can’t develop the necessary spin to form storms. Another ingredient is light winds higher up in the atmosphere. This allows the vertical structure of the storm to develop a strong circulation that ultimately becomes a hurricane. This becomes important when we talk about the impacts of El Nino and La Nina on predictions of tropical seasons, since El Nino years have much stronger jet streams in tropical regions than La Nina or neutral conditions do.

The curvature of the tracks is due to the mid-level winds in the atmosphere that steer the storms as they go through their life cycles. The counterclockwise flow of air around ridges of high pressure systems push the storms along their edges. This often results in a C-shaped pattern as the storm travels around the western edge of the oceanic high pressure, although the position and strength of the high pressure will help determine the path each storm takes and when or if it recurves to the northeast.

Depiction of a hurricane life cycle, from a tropical disturbance (easterly wave off the West coast of Africa) to a fully formed hurricane. Image credit: NOAA/NHC.

Impacts of tropical systems

Some impacts of tropical systems are only found near the center of the circulation, but others can be found hundreds of miles away, so even if you are not in the main area that tropical storms affect, you are not without risk. These storms are not small whirls like tornadoes, but are much bigger and can take hours to cross a location near the center. If you are close to the storm’s center, especially if you are on the right side of the storm’s path, you are likely to experience strong winds, heavy rain, and, if you are near the coast, the chance of a storm surge coming inland from the ocean. Farther away, you can experience strong squalls that include small tornadoes, heavy rains, and gusty winds. These effects are made worse if you live in mountainous areas where lifted air can cause rapid flooding conditions. Some of the worst floods in U. S. history are from former hurricanes that traveled over mountains and dropped incredible amounts of rain, such as Agnes, which caused the death of 122 people mostly in Pennsylvania, almost exactly 50 years ago.

Even after a storm weakens to a depression or transforms into an extra-tropical storm, the blob of moisture within the remains of the storm can be transported by the atmospheric circulation a long ways. There have been records of typhoons in the Western Pacific Ocean whose watery remains crossed the ocean and brought heavy rain to the West Coast. Occasionally some will enter the central United States and drop flooding rain there, too, such as the remains of Tropical Storm Erin in 2007.

Hurricane Dennis batters palm trees and floods parts of Naval Air Station (NAS) Key West’s Truman Annex, U.S. Navy photo by Jim Brooks

What gardeners (and everyone else) should know

Preparing a garden for a hurricane is no different than preparing for other types of extreme weather. Survey your property before the season to make sure that no objects that could blow around in high winds damaged are present. If a storm is coming, make sure that your yard is free of garden gnomes, rakes, damaged tree limbs, or other loose objects that could become airborne. Make sure your roofs and gutters can shed heavy rain and have a place on your property to contain rainwater safely. Have supplies of batteries, non-perishable food, and water for people and pets. Put together a plan to recover later by making inventories of your property, including outdoor equipment that you store online. And make a family plan for how to evacuate if you live in an area of flooding and how to contact each other later if you get separated. Cell phones often do not work after strong wind events, so you can’t count on them to bring your family back together quickly after a storm.

What’s next?

I expect to see the Atlantic tropical season start to pick up by mid-August, when the African dust that is currently inhibiting storm formation clears and the ocean temperatures get even warmer. In fact, today’s 5-day outlook map shows an area of possible development in the eastern Atlantic (as of 8-6-2022). This is expected to be another active season, and even though we’ve only had three named storms so far, we will likely see many more storms before the end of November, when the official season ends. In my next blog, we will look at the season so far in more detail.