Wild Temperature fluctuations mean it’s Spring in Tucson

Monthly Average Temperature for Tucson

The desert areas in Pima County, Arizona experience extreme weather most of the year. In relation to Tucson, it is safe to say that Spring consists of 2 weeks in March in which the temperatures are consistently between 75 and 90 degrees Fahrenheit. To hope for more than a short spring is just wishful thinking. Though graphs may say that the average temperature is more slow in changing, the actual change between the high 60-70 degrees of winter and the high 90-100 degrees of summer is very short - especially in the spring.


So what happens in Tucson’s spring? The mesquite trees begin to grow out their first leaves, insects start hatching, and gardeners keep growing their winter crop while hoping that they can begin their summer crop without having it freeze on one of the last cold nights of the season.

Average Hours of Sunshine per day

When is “all danger of frost” gone in Tucson? To answer this question I prefer to use the measure of what we call a “false start”. These usually occur in March. A false start begins when the temperature warms up for the first time in a while. There are no more freezing nights and everyone thinks summer is right around the corner. This weather pattern continues for about 2 or 3 weeks, and then the temperature drops and it freezes one last time. The deceptive first warming spell was called a “false start”. Beginning gardeners then realize that it wasn’t quite time to put those plants or seeds in the ground and that the cruelty of the desert climate requires gardeners to learn quickly.

After the last freeze – usually an outlier over the last 3-4 weeks – it is generally safe to plant the first of the frost sensitive plants. However, even after that point I still continue to use milk jugs filled with water to keep plants safe when temperatures drop to close to freezing. The water in the milk jugs protects the nearby plants via radiant heat. Radiant heat is helpful when outside temperatures are fluctuating wildly in the spring but can completely destroy my plants as summer-like temperatures approach. As soon as the outside temperatures rise above 90 degrees I remove all my milk jugs to keep plants safe and provide them with more room to grow. Concerns with radiant heat was one of the reasons why I was forced to plant my garden away from block or brick walls, which would otherwise cook my plants during Tucson’s summer days (and nights).
 

Radiant Heat is helps during temperature fluctuations

So, should you want to visit Tucson I would highly recommend coming in March. It is beautiful here now – though you will still need a jacket when it gets dark out. As much as I enjoy gardening here, extreme heat can really gnaw at you in the middle of the summer. As the Arizona summer bears down on us I’ll be wishing I was someplace north.



It's Spring here in Tucson

Long Term Storage of Seeds

Gardeners are often required to grow out their vegetable varieties to keep each kind of seed they have viable. Though there are many charts available online to help gardeners determine how long they can expect their seeds to last after harvest, many of these charts don’t help gardeners who may want to only grow their harvest out to seed every other year, instead of every year. What if I don’t want to grow onions or parsnip every year – does this mean that I have to buy new seed each time or anticipate that only half my seed will germinate after being stored for 2 years?



Some supplies for Long-term storage of vegetable seeds

Gardeners frustrated with the idea of growing out vegetable varieties just to preserve their hard-earned seed may take comfort in knowing that there are other alternatives out there. A few of the options to extend seed life include desiccating (or drying out) seed, storing seed in airtight containers and storing the seed at very low temperatures.



Silica Gel Beads from Southern Exposure Seed Exchange

Before putting seeds in a container, they need to be dried out properly. The reason they need to be dried is so that the seed's cell walls do not expand and burst when being frozen. Most garden seed uses moisture as one of the triggers to know when to begin the plant’s growth. However, when moisture is present without the presence of other growing conditions, moisture can cause vegetable seed age more quickly and, over time, the seed will fail to germinate. While several methods of drying seeds out exist, it is often difficult to know exactly how dry seeds are without the use of some form of material to desiccate the seeds. In order to prepare seed many seed-savers are now utilizing silica gel (or beads) to ensure that their seeds are dried out properly before moving their seeds into long-term storage. This is similar to the silica gel you may find in a container with new shoes, however this gel is used for garden applications. The silica gel is able to bring the seeds to a 2-3% moisture rate. I obtained my silica gel from Southern Exposure Seed Exchange. They sell a food-grade silica bead that is much safer to use around food than other varieties. When drying out seeds I put an equal amount of seeds, per weight, as silica beads in a glass jar to dry out. Note: if your seeds are already dry then be careful of drying them out any more! Over-drying seed can desiccate them so much that it can kill the seed.



Putting orange-to-green silica beads and seeds in jar

Storage container ratings from McCormack, 2004.

Once dried properly, the seeds should be kept in an airtight container to keep out the moisture. Although polyurethane (plastic) bags are often used to store seeds, these bags often let in small amounts of water. As a result, though storing seeds in plastic bags might be better than storing them in the open air, storage in glass jars with airtight lids will make the seeds last much longer. If mason jars are used, a new or unused seal is recommended for greater protection from leaking. There are other storage methods that are used, including metal lined polymer bags.  In general, the less the container that stores seed leaks - the longer the seeds will last. One research-based online article tells of several good ways to store seeds. 

A clean break when snapping a seed (right) is evidence of proper drying.

There are a number of studies that show that frozen seed can last longer than seed that is stored at room temperature including one from North Carolina State University and another one from a journal entitled Cryobiology. Additionally, some seed may be supported, rather than hindered, by being frozen. However, any seed that cannot be dried properly should not be frozen. When seeds with excess water content are frozen, the expanding water can damage the cell walls of the seed, causing the seed to be damaged and unusable. Remember that excessive desiccation of seed can lead to seed mortality as well.

Freezing Vegetable Seeds can help them last longer

Many gardeners have  noted that properly dried frozen seeds last 5 years or longer. The USDA also uses many of these techniques in storing their seed.  In one article, researchers in a 10-year study showed viability of properly dried frozen vegetable seed was similar to the viability that was originally tested seed.

All melon seeds from those that were not dried sprouted



All melon seeds from those that dried also sprouted



All seed sprouted - Strange that the frozen ones grew faster



Taken together – proper drying, storage and freezing of seeds may be the best way for seed savers to preserve their seed for future growing seasons and future generations. I experimented by sprouting seeds that had not been dried, had been dried, and had been frozen. All three were watered and sprouted within 3 days. My experience has shown that when proper drying, storing and freezing are used together, the germination of frozen seed is equal to original germination percentages. So next time you want to store some of that seed you have worked hard to harvest you might consider drying, bottling, and freezing your seed.



Can you sprout and grow seeds that have been frozen? Yes!

Thoughts about Seeds

I enjoy sharing and trading some of my excess seed with other gardeners. One way that I share my seed is through our local library’s seed bank. Recently Elena Acoba, a local writer, interviewed me about my thoughts concerning the Pima County Seed library in our local paper, the Arizona Daily Star. Apparently, I was contacted by virtue of the fact that I was one of the only people who left contact information with my donated seeds.



Seed Libraries help build community.


On a side note, Gardener’s Supply Company has this really interesting chart to guide you as you seek to start your seeds this spring.  I have moved from using the planting calendars to using charts like these because the decision to plant not just about what month it is but also what the recent temperatures were, what present temperatures are, as well as what future temperatures may be. I try to think about how air temperature trends affect the soil temperature before I plant.

Fertile Valley Seeds

Carol Deppe, the renowned author of The Resilient Gardener and Breeding Your Own Vegetable Varieties just released her 2013 catalogue from her small seed company (Fertile Valley Seeds). She runs the company once each year to sell off any excess seed she produces. So what does Carol have in her 2013 catalogue?

For squash she sells a supersweet Delicata, a Sweet Meat (C. maxima) squash and a Costata Romanesco summer drying squash. She also sells a very hardy multi-purpose flint corn variety called Cascade Ruby-Gold. The beans she sells include a Gaucho bush bean, a Black Coco bush bean, a Hannan popping garbanzo bean and a Beefy Resilient Grex bush bean. The Grex has a fascinating story of a cross that I never knew was possible. Carol also sells some Kale, a tasty romaine variety, a multi-purpose radish, an Indian Spinach, an edible Amaranth, and a Oregon Giant Sugar pea.


Carol Deppe developed the Hannan (Garbanzo) Popbean

For full access to Carol Deppe's catalogue you just need to email her a request for a copy of it. Her contact information is located on her website. She only sells her excess seeds once a year, so if you even think you might be interested make sure you email her. Last year I made the mistake of waiting a week to place my order and she ran out of seed before she could get to my order.





Founding Gardeners

While there are many books that can be categorized as either “informational” or “inspirational” there are very few books that are both. I found Andrea Wulf’s Founding Gardeners to be both informational and inspirational in every way. Wulf tells the story of how various gardens and farms shaped the life of those who signed the constitution. These gardens not only provided inspiration for the founding fathers, but also taught these men to be good stewards of their land as they looked forward towards the future of what America would become. As the author notes, “It’s impossible to understand the making of America without looking at the founding fathers as farmers and gardeners”.



Founding Gardeners is a great book!



Inspiration for gardening came to the founding fathers in many ways. I was surprised to find that as Jefferson and Adams sought for inspiration for their gardens while touring English gardens, they found these ornate gardens were filled with mostly American, rather than English, plants. This not only gave these men ideas in how they might use native plants to design their gardens back home, but also somehow encouraged their desire to establish the new nation.



Later, after the United States became more segmented and disjointed as a nation, the founding fathers turned to gardens to help them ease the tensions they worked to unite the nation during the Constitutional Convention in Philadelphia. Apparently, after the delegates to the Constitutional Convention were deadlocked on the decision of how congress would be organized, a group of them took a morning off to visit John Bartram’s nursery. After visiting the nursery, where they saw plants from all thirteen colonies growing among each other, these same constitutional delegates were able to return to their duties with a renewed desire to approve the Connecticut Compromise, the plan in which enabled for the establishment of the two houses of congress we know today. Though I knew that gardens could be inspirational and a place to relieve myself from the stress of everyday life, I had no idea how important a walk through the garden could be to those men who founded the United States.



One crop the colonists grew was wheat.



Many of the founding fathers looked at their farms and gardens as a reflection on themselves and sought to do all they could to care for their land. They not only cared about their land, but recognized that it needed to be replenished to remain healthy. Washington, Jefferson, Adams and Madison all sought to incorporate amendments such as manure, seaweed and river silt to their lands in an attempt to keep it fertile and healthy. Though Washington seemed to be the foremost expert on utilizing manure, after seeing the effects of successive tobacco farming on Virginia’s depleted soils Jefferson, Adams and Madison were quick to follow. Near the end of the book Madison gives a landmark address where he identifies the relationship between trees and healthy air, contour farming and erosion protection and emphasizes the importance of giving as much back to the soil as possible. The founding fathers cared about their land because they believed that as each farmer took care of his land, the crops would support him in protecting his rights in America’s new nation.

As the founding fathers looked forward to the future of the United States they were encouraged by the opportunity for growth that expanding westward provided. Each new area of the country that was explored provided the founding fathers with hope and encouragement as they learned about the many flowers, fruit, vegetables and trees now available to them. The westward expansion also provided for the expansion of the Agrarian, or farming, class. As fertile land became available, it provided the opportunity for individuals without fields of his own to claim his or her freedom by establishing farms in new territories. This was the hope of many of the founding fathers – that as citizens of the United States lived off the land they would be able to retain their inalienable rights and remain a free people.



I am grateful for the very ground I garden on



To anyone who enjoys history, gardening, or both I would highly recommend Founding Gardeners. This book is well written, informative, engaging and inspirational. It really helped me to understand how the enjoyment found in gardens could provide the founding fathers with a sense of inspiration, responsibility and a hope of the future of America. Having read this book, I am imbued with greater respect for the small seeds I plant and the soil I turn in my humble garden.