Stella Otto: The Backyard Fruit Gardener

Today's Tip: Mow vegetation short around the base of fruit trees and bushes to reduce winter habitat for rodents.

Water, Water Everywhere.…Or Nowhere

At the moment, for me, the well has run a bit dry; fig­u­ra­tively that is. This post is a bit behind sched­ule due to a minor case of writer’s block. My apolo­gies. Today I finally real­ized that could serve as inspi­ra­tion; inscrip­tion to write about how fig­u­ra­tive famine or flood might influ­ence the fruit crop.

Watering cans

Water­ing cans at the ready!

Late July is a time when, for many fruit gar­den­ers, the effects of water in the gar­den become mag­ni­fied.. For some, this year there has been a del­uge for oth­ers, drought. So, let’s dive in; rel­a­tively speak­ing and look at what you can do about it.

Too Much Water

For those areas of the coun­try that have been exceed­ingly rainy, here are some prob­lems you might be encoun­ter­ing and some sug­ges­tions for how to over­come them:

•    Fun­gus dis­eases. Fun­gus spores are spread and develop in the pres­ence of water. So lots of water, be it from rain or a sprin­kler, cou­pled with warm sum­mer tem­per­a­tures will encour­age growth of many dis­eases. Add ripen­ing fruit with softer skins and higher sugar con­tent and you face for­mi­da­ble prob­lems. The best approach is proac­tive. Keep fun­gus dis­eases in check from the very begin­ning of the sea­son. This is espe­cially impor­tant for some of the major dis­eases such as apple scab, brown rot, and mildew. Good dis­ease pre­ven­tion early in the sea­son equals fewer spores and sec­ondary dis­ease devel­op­ment at this time of year. If you have already missed the boat and dis­eases are sail­ing full-steam thru your fruit gar­den, con­cen­trated on sanitation—remove left over fruit that har­bors spores to avoid a seri­ous repeat prob­lem next year.

•    Water­logged soil. Roots need to breathe. They need some pore space in the soil for proper metab­o­lism. There is no quick fix for this. Reg­u­lar addi­tions of organic mat­ter and com­post will improve soil tex­ture over time (some­times lots of time.) If you are select­ing and prepar­ing a site for new plant­i­ngs, keep drainage in mind to min­i­mize or avoid this prob­lem in a rainy year. Check here for more infor­ma­tion on soil tex­ture and drainage. Water­logged soils often causes the next symptom:

•    Yel­lowed leaves & defo­li­a­tion. These are two out­wardly vis­i­ble symp­toms indi­cat­ing your fruit trees or berry bushes may be encoun­ter­ing a mois­ture prob­lem. The prob­lem could be either excess, more likely if the leaves are yel­lowed; or insuf­fi­cient water. If the prob­lem is excess, the solu­tion was already men­tioned above. We’ll address lack of water later on.

•    Nutri­ent leach­ing. Nitro­gen espe­cially, is quite water-soluble. Exces­sive rain­fall or over-watering may carry it through the soil and out of the plant root’s range. If you are expe­ri­enc­ing lots of heavy rain, it may be worth­while to feed smaller doses of nitro­gen more often; for exam­ple 1/3 of the annual dose bro­ken into 3 applications—one in early spring, another dur­ing fruit swell and the last a month later as the crop is matur­ing. Avoid fer­til­iz­ing beyond mid to late sum­mer or plants may grow too suc­cu­lently and be sus­cep­ti­ble to cold injury at the start of the winter.

Not Enough Water

Although solu­tions to dry con­di­tions may involve tem­porar­ily more work on you part, drought may be eas­ier to deal with (at least you can try to pro­vide mois­ture) than a non-stop del­uge that is hard to deter. Let’s look at the flip side of the “flood” prob­lem and what you may be able to do about it. Some prob­lems that may crop up include:

•    Wilt­ing. This is the first and most com­mon sign of a plant in water stress. The obvi­ous solu­tion is to pro­vide water to sup­ple­ment what nature has failed to pro­vide. Trickle irri­ga­tion is an effec­tive and water con­serv­ing way to do this. One thing to remem­ber with trickle, is that it needs to be started early in the sea­son, before the ground has truly dried out. It is not easy to replen­ish the soil reserves with the small quan­tity of water pro­vided by a trickle sys­tem. The ben­e­fit of trickle irri­ga­tion is that it pro­vides mois­ture directly in the root zone, where it is most needed with­out wast­ing excess water.

•    Scorched leaves and defo­li­a­tion. These two symp­toms are seri­ous indi­ca­tors that your plant is suf­fer­ing more severely. Again, you will have to step up and fill the water gap. Espe­cially if you did not start trickle irri­gat­ing ear­lier you may need to pro­vide a deep soak­ing, either by hose or bucket, to fully wet the root zone and bring the plant out of stress. If you are under water restric­tions con­sider col­lect­ing gray water (from cook­ing, hand-washing, and other tasks where water may be “dirty” but not unus­able.) As long as there are no pes­ti­cides or high lev­els of salts or fer­til­iz­ers in the water, it should still be usable for plants. Once at least mod­er­ately reju­ve­nated, you can con­tinue to main­tain your fruit trees, berry bushes, or vines with trickle irrigation.

•    Death of young trans­plants. Newly planted fruit trees and bushes are more sen­si­tive to lack of water since their root sys­tems are not yet fully devel­oped. Close mon­i­tor­ing and extra TLC, in the form of timely water­ing, are crit­i­cal under drought con­di­tions. You can learn more about how much water you need to pro­vide here. [LINK]

•    Small fruit size. Fruit size often suf­fers when the plant expe­ri­ences a seri­ous water deficit. You can help the plant by thin­ning the fruit a bit more aggres­sively. With a reduced num­ber of fruit the tree or bush has to sup­port, it can chan­nel its energy into prop­erly devel­op­ing the remain­ing crop. Hard as it is psy­cho­log­i­cally to remove fruit from the plant, it is a wise short-term sac­ri­fice for long-term gain.

•    Pre­ma­ture fruit drop. This symp­tom of mois­ture stress is one step beyond, reduced fruit size. In self-preservation, the fruit tree or bush will drop fruit that it can no longer sup­port. You will do your water-stressed fruit gar­den and your­self a huge favor if you thin fruit early as sug­gested above.

•    More severe dam­age by pests. Drought-stressed fruit trees, berry bushes, and vines are weak­ened plants. This leaves them more vul­ner­a­ble to pests. Mites tend to mul­ti­ply rapidly in hot tem­per­a­tures that often accom­pany drought. Mites suck­ing sap from already dried leaves exac­er­bates plant stress. Bor­ers often find it eas­ier to invade weak­ened tis­sue and often do more than the nor­mal amount of dam­age in times of drought. Be espe­cially vig­i­lant for signs of these as well as other pests and imple­ment con­trol steps quickly in order to main­tain plant strength.

•    Root rot and other dis­eases. Weak­ened root tis­sue often sets up the oppor­tu­nity for soil-borne root rot organ­isms  to enter. Armil­laria root rot as well as Nec­tria and Cytospora canker on stone fruit are par­tic­u­larly oppor­tunis­tic. Symp­toms are not likely to occur imme­di­ately. Rather the dam­age will make a delayed appear­ance a year or two later. Be pre­pared and try to proac­tively pro­vide opti­mum care to your fruit gar­den to keep it strong next sea­son and in the years to come.

Moisture-related Prob­lems in Spe­cific Fruit

I’ve cov­ered gen­eral rec­om­men­da­tion for man­ag­ing water needs in the fruit gar­den dur­ing unusual rain­fall or lack thereof. Let’s look now at a few spe­cific fruits and their unique situations.

Straw­ber­ries. Nor­mally straw­ber­ries are given fer­til­izer fol­low­ing ren­o­va­tion rather than early in the spring. When ren­o­vat­ing dur­ing drought con­di­tions, you may want to reduce the amount of fer­til­izer or split the appli­ca­tions, sav­ing some of the appli­ca­tion for when nat­ural rain­fall or ade­quate water sup­ply becomes avail­able. Reduc­ing fer­til­izer may reduce growth of new plants, which is not ideal, but it will also reduce the amount of leaf area for mois­ture loss through tran­spi­ra­tion. It is a trade-off that you will have to judge based on your indi­vid­ual sit­u­a­tion.
Sweet cher­ries. Fruit crack­ing often occurs when there is rain­fall shortly prior to har­vest. Lit­tle is under­stood about the rea­sons why this hap­pens and researchers are still search­ing for what can be done to pre­vent it. At the moment any pro­posed solu­tions are far to com­plex and expen­sive for home gar­den appli­ca­tion. The only mar­gin­ally effec­tive solu­tion for the home gar­dener may be to choose less sus­cep­ti­ble vari­eties, but even this is not a guar­an­tee. Van, Sweet­heart, Lap­ins, Rainier and Sam could be vari­eties to con­sider. Bing cher­ries have a high inci­dence of crack­ing and may be best avoided in areas where fruit crack­ing is a fre­quent prob­lem.
Peaches and nec­tarines. Split pits in peaches is not fully under­stood and can hap­pen even in seem­ingly “nor­mal” grow­ing sea­sons. Two fac­tors that may make it more preva­lent in sea­sons of drought are one, the rec­om­men­da­tion to thin fruit heav­ily and two, the sud­den excess of water the fruit may receive from rain­fall if drought ends or if watered heav­ily at the time of pit hard­en­ing and fruit swell. Both these fac­tors appear to make split pits more com­mon in sus­cep­ti­ble varieties.

Gen­eral Prac­tices for Effec­tive Water Man­age­ment in the Fruit Garden

To close, remem­ber that the fol­low­ing prac­tices will help effec­tively pro­vide con­serve, and main­tain ade­quate mois­ture for your fruit gar­den under nor­mal rain­fall:
•    Apply mulch around the base of fruit trees, berry bushes and fruit­ing vines.
•    Trickle irri­ga­tion should be started before soil mois­ture reaches a deficit level.
•    Water dur­ing the coolest part of the day.
•    Dili­gent con­trol of weeds reduces com­pe­ti­tion for mois­ture.
•    Pro­vid­ing an appro­pri­ate amount of water reg­u­larly is impor­tant for strong plant and fruit growth.
•    Time water­ing to coin­cide with crit­i­cal growth periods—root devel­op­ment, fruit swell, flower bud initiation—if your water sup­ply is limited.

So folks, when it rains, some­times it pours. Let’s hope that all our gar­dens receive the appro­pri­ate amount of rain­fall for the remain­der of the grow­ing sea­son and that my ink well (or key­board, as the case may be) is also duly replenished.